I'm sure others have written more comprehensive guides, but I felt like writing this up as a break between other tasks, and then expanded on it after getting commentary from friends who've played longer than I have. This isn't a full walkthrough, but it still counts as giving some spoilers, so if you've never run Montague's arc on the hero side of the game, stop reading now. You really should do this once without spoilers, for the sake of the story elements.
    I won't really be covering the villain side, since I've only done it a couple times. In any case, it has a larger number of mobs that have to be fought, so there's not as many ways to trim time off the mission other than the coattail-riding trick.

    If you're the sort of player who only runs a couple of characters, this guide probably isn't for you. You won't be seeing Percy enough to be sick of him, and you might want to try the arc out at different levels to see how the change in enemy types matters (for instance, seeing Behemoths and Chief Mesmerists instead of Guards and Scroungers). But if you like to create new characters a lot, you're probably already tired of the Midnighter arc, or will be soon. This guide is meant to help you get through it as quickly as possible, so you can unlock all the goodies and move on to content you're NOT tired of.

    Why bother in the first place, if it's such a bore to you? Several reasons, really.

1. Until and unless things change, the only way into Cimerora is through the Midnighter Club. So if you want to take part in any of the missions or task forces there, you need to run Monty's errands. It's possible that Cimerora will eventually open up in the same way Vanguard did, in which case I expect Monty will get lonely.
2. The Midnighter Club store has L35+ single origin enhancements for all origins, increasing the number of places you can get to a Single Origin store in Paragon City. Vanguard bases also provide this benefit with no entry restriction, but there's two zones with a Midnighter entrance and no Vanguard entrance in Paragon (Steel Canyon and Croatoa), so access to the Club can save you some time. Even in Founders' Falls, the fact that the Club door is very close to Infernal means you can just pop over to buy enhancements after leveling up in the zone, rather than risking the ever-present snipers to get down to the Vanguard DPO or one of the in-zone stores. For villains the only Midnighter entrance is just down the street from a Vanguard, so villains gain no real benefit here.
3. On the hero side, the Midnighter Club offers zone transit between the south side of Steel Canyon, Croatoa and Founders' Falls, removing the need for a trek to or from the Green Line in some cases. Additionally, if you want to get to the north end of Founders' Falls without dealing with snipers, it can be convenient. Again, no real help for villains, who only have one Midnighter Club entrance (although once Going Rogue hits, that one Rogue Isles entrance leads to three Paragon City exits for those who are allowed to travel between sides, two of which don't have Pocket D exits or Vanguard exits).
4. There's a Heal Ally day job accolade power ("Revitalize") that you get if you finish off the day job badges for Hospital and Midnighter Club, which is nice for both heroes and villains.

    The Coattail Trick: The absolute fastest way, either hero or villain, is to find someone who is about to do the final part of the arc ("Enter the Midnighter Club") and ask to be on their team, but you can't really count on being able to ride their coattails like that. ;)

    Soloing: Barring coattail-riding, soloing Monty's arc seems to be the way to go, because almost every segment of it favors soloing for one reason or another. There's one part that doesn't, but it can be dropped if you have a mission drop available (most of the other parts can not be dropped, by the way, an exception to the "you can drop anything but timed missions and major arc endings" rule).

    In addition to having a mission drop available, the following things tend to help in rapid soloing of the Midnighter arc:

1. Ninja Run. It's just the right speed to stay controlled on indoor maps while letting you get through an enemy's "aggro zone" quickly. If you have good enough control to use Flight or Superspeed indoors, they'll do the job as well. Teleport can at least reduce the number of mobs you need to fight, but it's not that useful in the twisty indoor maps. Superleap doesn't help at all. The L14 Afterburner power in Flight gives you speed and control, although the "Only Affecting Self" part means you could be in trouble if you get stuck on a corner at the wrong time.
2. If you don't have Ninja Run, then any stealth power, so you can avoid enemies noticing you in the first place.
3. Any "travel power" since there's a lot of running around to get to the missions (especially in what I call "Part 5" below). If you haven't taken one yet (they're now available at L4), then Ninja Run or Rocket Board will do as well.
4. Being low level enough that Aberrants and the like don't spawn, so you don't have to worry about being Held or Slept. At level 14, you won't see anything bigger than a Headman.
5. Being high enough level to ignore attacks from Perez Park mobs, so you can cure Lost more quickly. At level 14, you'll have to be more careful in Perez.

    In parts 1-3, it's absolutely VITAL that you have some way to avoid most of the mobs, though. Sprint alone isn't fast enough to pass through the range of a mob without a good chance of being taken down, you need to either have a stealth power or fast movement that works indoors for you. Some defense sets will let you survive running past with Sprint, though, like the Personal Force Field power or a good Defense buff.

    (Aside: if you have a "ninja taxi", a character with good stealth and the ability to teleport allies using either Recall Friend or an Assemble Team ability, then a lot of the soloing tricks can be used by teams as well, letting the ninja taxi run to the goal and then summoning everyone else to help fight the enemies.)

    After soloing a few dozen characters through the arc I've found that, barring a few specific power combinations and archetypes, levels 14-16 seem to work best for soloing this arc, using Ninja Run to avoid the need for stealth powers. I've successfully run the arc at level 10 with a Scrapper, but the travel missions take longer if you don't have a travel power or at least the Rocket Board.

    I will note that on the first three missions, if I'm playing a character who's good at soloing, I will often speed-complete the mission and then clear it backwards, since if I accidentally bite off more than I can chew at that point I can always exit the mission before I die. That doesn't work so well in a team, where each person who bails makes it harder on the ones who remain behind. :)

    Okay, now a breakdown by mission, explaining why I suggest the mix of powers and levels. Keep in mind, the goal here is to finish the arc quickly and without dying (since dying tends to cost you time, especially if you die with an enemy still standing over you and can't use an Awaken), not to gain the best balance of XP-per-minute. The arc isn't really very good for power leveling to begin with, so you might as well just get it over with quickly. With practice (and Ninja Run), you should be able to complete the whole thing solo in under half an hour with just about any archetype, since the point of this strategy is to avoid combat as much as possible.

    Part 1 (rescue Percy): This is a randomized map with Percy in a different place every time, so I suggest using a keybind to help find him ("/bind ADD targetcustomnext percy" will target Percy when you hit the + on the number pad if he's in your view, useful since he's usually cowering behind someone and barely visible to the naked eye). He's always in a room, though, never in corridors, so race through the corridors as fast as you can and only stop in open areas with minimal risk of aggro. Fly or Hover really helps here, since at lower levels you're likely to be safe from notice if you get to the ceiling. At lower levels you're also unlikely to spawn any threats that can stop you dead with one shot, and even squishy archetypes can take a few shots in passing from Archers and Spectrals.
    Soloing is favored here simply because of mob sizes. The gaps between mobs are larger, making it easier to find a spot to stop and rest if you get tagged in passing. Also, this mission ONLY requires you beat the enemies guarding Percy, with larger groups there's a greater chance of getting adjacent mobs involved.
    A warning about trying to use Flight or Superspeed on this map: the torches are really easy to get hung up on at high speed, leaving you stuck long enough to take serious damage from an attacker. Even Ninja Run is often a little too fast to be controllable in these corridors, and unlike the static map of parts 2 and 3 you don't benefit as much from repeated practice. If you have a Stealth power, you might try just Sprinting it even if you have a faster movement power.
    This mission is usually in one of the park areas along the west side of the map, not too hard to get to safely even for L10 characters. However, since you need to go back to Monty at the end of this part (you get his cell number after checking in), a travel power is helpful. Since I20, it seems to be placed in the southwest corner more often, but that may just be luck on my part.
    So, strategy in a nutshell: Ninja Run (or Stealth, or use Flight or Superspeed) through all the corridors, stop in each room and survey it for Percy, then take out his guards and punch out.

    Part 2 (Ci'Dion the first time): This mission is often at the north end of Steel Canyon, and you had to return to Monty after part 1, so keep in mind that you can take the train from South Steel Canyon to North Steel Canyon. If you're running this below level 16, though, you might have trouble with the random enemies on the street on the north side, so a Raptor Pack at least keeps you above the fray if your travel power is Superspeed.
    The map for this part and part 3 is always the same, so after a few runs you should get the hang of things and be able to run it even more quickly, even trying things like Flight or Superspeed. When I first started playing, the final room with Ci'Dion was sometimes on the right branch of the cave network and sometimes on the left, but one of the updates around issue 15 or 16 seems to have changed that...every time I've run this map lately (about 20-30 missions) the boss room has been in the left branch. The hole in the floor of the office building has always been the left branch as long as I've been playing (left side when facing the hole from the hallway). Even if it starts randomizing again, though, it won't take you too long to backtrack and try the other side.
    At the really low levels, you won't spawn anything bigger than a Headman, so the worst you'll get for status effects is a knockdown. However, in the mid to upper teens you'll start to see Aberrants, which can put you to Sleep, so be sure you have a couple of Break Frees. Then just Ninja Run the mission until you get to the boss room. You'll need to clear a handful of guys around the room, plus Ci'Dion's posse in the back. Ci'Dion's mob is probably the single toughest thing you need to defeat in the whole arc (there's nastier stuff around, but you can generally leave it alone), but even a solo Defender can generally take care of him and his backup band.
    I've only run a couple of Kheldians through the arc so far, so this may just be my bad luck, but it seems like if you have a Kheldian in the mission that Ci'Dion's mob will contain a Nictus of the appropriate level. This can make the room tough to solo, since Quantum guns and their ilk tend to knock humanform Kheldians around like bowling pins.
    Soloing is favored in this part and the next because it's a lot easier to sneak past the mobs to get to Ci'Dion's room, and you're less likely to get multiple groups attacking you at once in Ci'Dion's room.
    Nutshell: run to Ci'Dion's room, clear it, click on the computers. Then clear backwards if you feel like it.

    Part 3 (Ci'Dion's Encore): This is always in the same location, East side of Steel Canyon roughly midway between North and South ends. There's some bent parking meters outside the mission door that can be stood upon (regular ones have rounded tops so you slide off) if you so desire. It's also the exact same map as part 2, with many of the same spawn points. So, just like part 2, run your way to Ci'Dion's room.
    The difference here is that rather than being at the back of the room with a bunch of goons, Ci'Dion is usually near the entrance all alone (especially if you're soloing). So all you need to do is take out the couple of guys guarding Argot'BurWot, clean up one or two other guys wandering around, and take down Ci'Dion again (in whatever order you like, you can probably sneak past Ci'Dion and leave him for last if you prefer). Since he's all alone, it's easier than in part 2 so long as you don't accidentally wake up an unrelated group. Ignore what Argot says about you following him, by the way, his translator is more broken than most and he's saying he'll follow you.
    Nutshell: Same as part 2, but easier.

    Part 4 (Lady Jane): Okay, this time the main reason to solo is that you want to fail. If you're teaming the arc, everyone has to fail before everyone can move on to the next part...cooperative completion only works on success. And keeping Lady Jane alive is very tricky no matter the team size, since she will attack everything in sight. (Aside: if you want to succeed in this mission, your best bet is to find a way to avoid her entirely on the way in, clear everything else and locate the treasure chest yourself, then come back and free her...you can generally outrun the first wave of ambushers if the route is otherwise clear. Exactly how you avoid her will depend on your team size and powers, but Confuse and Stealth tend to be useful, along with Teleport and Recall Friend and its variants. Most successful strategies involve the "ninja taxi goes to the chest and then everyone clears backwards to Jane" theme.) Don't worry, when you fail you still get the relevant Clue and Salvage, so you don't have to do it over if you're soloing. You get less mission-based payoff, but as mentioned earlier this isn't really a mission arc you do for the XP (and at lower levels any salvage or recipe you get for successful completion probably won't be worth much).
    So, when you solo, you take out the first mob you see, since it's between you and Jane. Then you free Jane and annoy everything around her... then run away. You may want to target Jane first, so you can watch her Health. But the idea is to let her take all the attacks from the guys you woke up, so she dies faster. You could also just free her and run away, but the ambushes alone take longer to kill her and don't always get into her aggro range on their own (she only dies quickly when you don't want her to die, in accordance with Murphy's Law). If your character is either too good at holding the attention of the enemies (a Tanker) or too squishy to take a lot of attacks before shaking pursuit, you may want to just let the ambushes get her. And if she somehow survives all of them, I guess you'll just have to complete the mission. This is probably the longest of the non-droppable missions in the arc, even on speed-complete.
    Warning, even if you're running this at level 10, you will have to worry a little about status effects here. The wimpiest guard Lady Jane can have is a Madness or Ruin Mage, and if he tags you at the wrong time you could be locked down. So be sure you have a Break Free on hand.
    This mission can be in any of the locations where Percy's mission can be located, but since you'll be on the far East side when you get this mission, you still want that travel power. It's a "dry cave" map, so it's easier to navigate with travel powers than the torchlit tunnels of part 1 or the office building that opens parts 2 and 3.
    Post I20 Addendum: I'm not sure if I'm just getting better or if they made Lady Jane less stupid/fragile, but I've had no trouble with a straightforward "rescue Jane, clear the way to the chest" strategy the last several times I've run this.
    Nutshell: Free Lady Jane, run away and let her get killed like the Leeroy she is. Or don't, she might be less Leeroy-ish than she used to be.

    Part 5 (Errand Boy): Actually, this is several missions, but I'm lumping them all together. You go to Atlas to talk to Argot, then run some stuff to Azuria, then craft the Lost Cure. Here's where you want that travel power. Also, if you're on a team, anyone on the team who isn't working the arc gets to sit around and twiddle their thumbs while you race around, another reason to solo it.
    When it comes time to craft the Lost Cure, a recent change to the game can make this a bit shorter. Rather than having to go back to Steel Canyon and the University, you can run to Vanguard and use their crafting tables (and grab the Vanguard Operative badge while you're at it). All in all this only really saves you time if you plan to hunt Lost in the Hollows, though, since the Lost in Perez are near the Steel Canyon entrance and your total travel time will be about the same either way.

    Part 6 (Cure Lost): If you can drop a mission, you might want to just drop this one. Even at its best it can be a bit tedious, thanks to the long recharge time of the Lost Cure. It does work faster with a team, although any teammates who have done the arc before will only get to cure one Lost before their wand vanishes.

    If you're under L15 or so, some character builds will have trouble surviving the Perez Park mobs, so go to the Hollows. Lost have their own hill, it's almost against the North wall and the farthest west of the hills in that cluster. They all spawn from L5-9, so you can generally ignore them and set the Lost Cure on automatic (control-click the icon). You get no XP for curing a Lost regardless of the level, so the fact they're five levels below you won't make a difference.
    At higher levels, you'll want to go to the North end of Perez Park, since the relevant neighborhood is rather close to the University in Steel Canyon. Two or three mobs will generally do the job, depending on how badly they scatter and whether any other players are farming...er, curing the Lost at the same time. If you're not too much higher than the level of the Lost, they will attack you, but if you seriously outlevel them they will prefer to attack their cured brethren. If they do attack you, the long recharge time of the Lost Cure means you might be better off playing hit and run with Flight or a Raptor Pack (or Superleaping onto the tree canopy).
    The mission statement actually lists several other zones where you can go hunt for Lost to cure, but you have to go farther afield to find them (for instance, the north end of King's Row, away from any links back to Steel Canyon, or the north end of Faultline which is several zone changes away from Steel Canyon even if you take a short cut through Pocket D).
    Nutshell: Go to the Hollows or Perez and clean up a few mobs.

    Part 7 (enter Midnighter Club): This is a simple "go somewhere" mission, no need to find a way to make it shorter. However, if you don't have a pressing need to get into the Club, you might want to leave Monty hanging on the phone and not accept this mission yet. Why? Because you might have a friend later on who needs to get into Cimerora, you can team with them long enough to get them into the Club without them having to run the entire arc. Or, if you're feeling mercenary, you could offer to bring a bunch of people in for a suitable gratuity in terms of Influence. By this point you have Montague's phone number, so you can always call him up and ask for the mission once you're ready.
    Once inside, you might want to do the Midnighter Archivist badge scavenger hunt (vidiotmaps.com will show the approximate locations of the targets if you want). If you're not into history badges in general, it might be your only history badge, and thus selecting "History" from the badge dropdown is an easy way to go back and check to see if you completed the arc in the event you don't keep careful track of this sort of thing. And if you're into history badges, you'll want it for its own sake. :)

    Finally, in case you don't get the reference, one of the incorrect answers to give the Latin Student ("Cuando Omni Flonkus, Moritatus") is the motto of the fictional Possum Lodge, from the Red Green Show. It means, "When all else fails, play dead." And remember, I'm pullin' for ya.

    First off, as mentioned above where I told you to stop reading, if you haven't done this arc at all you should do it at least once "the hard way." The Midnighter arc is part of one of the game's big storylines, the mystery of the Rikti invasion. You should definitely do this arc in full at least once before you start doing the Rikti War Zone arcs, where most of the rest of the mystery is laid bare.

    Now, for all that some parts of it get old really fast, the arc isn't totally without replay value. So, in the interests of balance, here's a few reasons to play the Midnighter arc (or at least parts of it) more completely on later run-throughs.

1. It scales to every level from 10-50, with a different variety of threats in each level range (although part 6 doesn't scale). Circle of Thorns is one of the only villain groups with representation at pretty much every level, from human cultists to ancient demons. So, even if you tend to shy away from Thorns-based contact missions, you can get to see pretty much all of their enemy types simply by playing the Midnighter arc at different levels for different characters. Similarly, while the Lost only really scale up into the 30s or so with the Pariahs at the top end, actual Rikti get substituted in for them at higher levels. Mind you, if you want to fight Rikti, there's plenty in the Rikti War Zone, so there's not a lot of motivation there. (By the way, Ci'Dion never really gets any tougher at higher levels, he still folds like a lawn chair. His shoulderpads are insufficiently big for him to be a credible threat.) But it does mean that rescuing Percy and meeting Lady Jane result in different challenges as you level up.
2. Lady Jane is a definite challenge (although this may have changed somewhat since I20). She's a bigger Leeroy Jenkins than even Fusionette, there's more ambushes, and even at level 14 you're seeing some fairly scary demon types that will stay interested in you and chase you halfway across the map before giving up. If you want a challenge that's more than just "higher level baddies", actually trying different tactics for keeping Jane alive can provide it. Sure, having the ninja taxi get everyone to the chest and work backwards is tried and true, but there are other ways around it, and you might enjoy trying to find those ways.
3. If you're high enough level that the Lost mobs ignore you in Part 6 (pretty much all the Lost in the Hollows or King's Row no matter what, although you need to be about L17 in Perez or L20 in Faultline), then you can stand there and watch in amusement as the uncured Lost try to attack the cured Lost. Civilians are unkillable, so the effect can be comedic in a schadenfreude-y way. Just be sure you turn off any automatic attacks or you might accidentally kill a Lost you're trying to cure.
4. Badgehunting. You can pick up the Finder badge by taking out 100 Lost bosses, which happens pretty quickly if you run this arc with a team in the level range where Aberrants, Eremites and Pariahs spawn. Even without taking side trips to totally clear them, there's over a dozen mobs between you and Ci'Dion in each of parts 2 and 3, and with a full team of 8 you could see three or four bosses in each mob. Similarly, the Weed Whacker badge is gained by defeating Succubi and Hellfrosts, which will appear if you run parts 1 and 4 at a high enough level. The Soul Binder badge is gained by defeating Circle of Thorns mages, which spawn in various types and numbers at pretty much all levels of part 1 and 4.
5. Concurrent "pelthunting" mission. It turns out that if a "Defeat N (enemy type)" mission doesn't specify where you have to do it, then victories attained in other missions will still count towards your total. If you get what I call a pelthunting mission (after the fantasy game grind where you're asked to bring back a dozen wolf pelts or whatever) and you don't like your odds in fighting the "wild" versions, picking an arc mission that spawns that enemy type will make sure you get them at a level you can handle. The most common of these is the Aura-unlocking mission, which requires defeating 15 Rikti. By level 30, you're getting Rikti showing up in parts 2 and 3 of the Midnighter arc in addition to Ci'Dion himself, so you can finish off the pelthunt without worrying about getting slaughtered by over-powerful random spawn Rikti in Crey's Folly (although if you know where to look, you can fulfill the Aura pelthunt with Rikti Monkeys near the Crey's Folly entrance, just hope no Nemesis sniper types spawn too close to the door).
6. Calibration. Once you've done this enough, you should have a good idea of how hard it is in an absolute sense. If you suspect a particular new combination of powersets is either really good or really bad, you can take the character or team through this arc to see how well they perform. Since many of the normally variable stuff like maps and spawn points are locked down in parts 2 and 3, it provides a control. Okay, I doubt this is a motivation for many of you, but the Positron-types out there might appreciate it.