Reilly's Rangers are a mercenary group operating in the Capital Wasteland. Their current missions are the ongoing eradication of super mutants, and mapping the Wasteland. The five members of Reilly's Rangers are:
Make your way through the hospital and up to the second floor. This will require fighting or sneaking past the super mutants and one of the game's several centaurs. There is at least one pressure plate and several tripwire-activated grenade bouquets, set by the Rangers.
Cross over to the Statesman Hotel by walking across the toppled crane. Drop down into the hotel.
Meeting up with the surviving Rangers on the roof :
In the first stairwell you will find the body of the Rangers' quartermaster, Theo, and a locked ammunition box which can only be opened with a code received from Reilly (see #1.2).
At an intermediate floor, you must go up to the restaurant level. If your Repair skill is high enough, you can fix the elevator at the center of the map by interacting with its control panel. If not, you can also use the stairs through the doorway at the building's northeast corner.
On the restaurant level, you'll need to pick an average lock or (to avoid it) you can detour around the lounge, down a collapsed floor into a lower level, up another collapsed floor, through the kitchen, and into the lounge proper (the room with the bar, pool table, and jukebox). In the southwest corner of the lounge there is a small room with a downed maintenance protectron. This is the only available fission battery if you did not bring one with you (see #1.1). In the lounge (the big room) go up at right to the balcony where you'll find the door to the roof.
Repairing the elevator to the ground floor :
As you arrive on the roof, a final round of explosions will take out the latest wave of super mutants. Butcher will then wave you in, but admits you're stuck there with them unless the elevator can be repaired by Donovan.
You may speak to each team member and, if you wish, offer them ammunition (Brick takes 150 5mm rounds, Butcher takes 50 10mm rounds, Donovan takes 50 5.56 rounds).
Ask Donovan about the elevator and he will tell you that he needs a fission battery and will mention the broken protectron in the restaurant below if you don't have one with you.
Give the battery to Donovan and he will repair the elevator or ...
If you have a Repair of 75 or higher you can fix the elevator yourself by accessing its control panel with the fission battery in your inventory. (This will not use it up.)
WARNING: If the fission battery is somehow lost, the elevator becomes irreparable and the PC will be unable to exit the hotel. Check the notes section on The Statesman Hotel article for an escape method. The fission battery can be very difficult for some to find. The last large room before you reach the roof has a bar area, some pool tables, and a jukebox. This is the same room with the Grognak the Barbarian. In the southwest corner of that room (not the entire floor, just the room), there is a door under the stairway. That door goes into a small room with the broken protectron. There is where you'll find the fission battery.
After rescuing Reilly's Rangers, if you offer to help Reilly with the Rangers' mapping duties, she will give you a geomapper module. As long as you have the module in your inventory, it will record every new location you discover. Return to the Compound periodically and speak to Reilly again to receive 30 caps per location. You can speak to her right away after first receiving the module and get paid for locations you've already discovered**.
There may be a minor glitch upon talking to Reilly about the geomapping. She may say that all the locations you mapped before receiving the module were already found, and that you need to find "new" locations to receive any payment. This can be avoided by not trying to 'cash in' right away; leave the Compound and discover at least one location, then return to Reilly, and you will be paid for every location on your map.
It is not enough to simply have the locations on your Pip-Boy map (as can be gained from the Explorer perk or from Karen Schenzy after the Blood Ties quest). To gain the caps these locations have to be "discovered" by actually visiting them.
If you repair the elevator as opposed to giving the fission battery to Donovan, you'll gain additional XP.
If you revive Reilly yourself, there's a chance that she will stand up in a slumped and tired position and stay that way indefinitely (even after the quest).
If Donovan is killed on the roof in the battle with the super mutants, you can use Donovan's wrench to fix the elevator.
You may randomly encounter Donovan while traveling through the Capital Wasteland. When you talk to him, he will give you a mini nuke and say that Reilly sent him. It's also possible that your random encounter with Donovan will be the discovery of his body, on which you can find his Ranger battle armor, a Ranger battle helmet, a 10mm pistol, a mini nuke and a few random items.
On Reilly's terminal, there is a contract note about being paid for each super mutant killed and needing body parts as proof.
When you arrive at the roof of The Statesman Hotel, there is a generator to the left that, when shot, will turn the Rangers hostile and the quest will fail.
You cannot go up to the lobby by elevator, as it is powered down - you need to go by stairs.
After the fixing the elevator and leaving the roof there will be a wave of super mutants that attack. You can let Brick get killed and pick up Eugene and the Ranger battle armor so you do not have to choose only one of them as the reward. It is also possible to shoot Brick yourself at this time without the other Rangers becoming hostile to make sure she is killed.
pcps3xbox360 If you have Colonel Autumn's laser pistol, or Allistair Tenpenny's suit in inventory or if you have Fawkes, Charon, or Dogmeat in your party when you make initial contact with the Rangers on the roof of the Statesman Hotel, Reilly's Rangers may become hostile to you, so have any follower and Dogmeat wait in the hallway of the previous area, go make initial contact with the Rangers, then return to the prior area and retrieve your follower. May be caused by Brick dying at the hands of super mutant overlords at higher levels, or explosions. If Brick dies at any point the Rangers may become hostile to you. Load the auto save and try again until she lives. This may also happen if Sydney is still with you from Stealing Independence. [verified]
xbox360ps3 As long as Brick dies, the Rangers will become hostile towards you; no follower is needed.
pcps3xbox360 The same broken protectron can be found stuck in the floor after initially going to the rooftop and looking for the fission battery after speaking to the Rangers. The protectron will fall halfway through the floor and will make the noise of metal falling onto the floor repeatedly. If this happens just run towards the noise and then just proceed normally once obtaining it. [verified]
ps3 When talking to Reilly in the Rangers HQ, the game may crash, resulting in being returned to the main menu. [verified]
ps3xbox360 There is an audio bug which affects all of the Rangers' voices. It will cause dialogue to proceed exceedingly quick making text impossible to read, and audio dialogue will not play at all, leaving the player to respond to dialogue he/she has not been able to ponder. Although the quest can be completed regardless, it is still bothersome, and can hamper understanding of how to proceed. [verified]
ps3xbox360 Reilly's Rangers may randomly become hostile to the PC upon return to their HQ.If this happens just reload the save until they are not hostile.This may be because the super mutants are not dead when you get to the Rangers. [verified]
xbox360 If you have Colonel Autumn's laser pistol, or Allistair Tenpenny's suit in inventory, it may disappear upon completion of the quest. [verified]
ps3xbox360 Reilly's Rangers may become hostile towards the PC if you shoot one of the Ranger's corpses should any of them die after the elevator is repaired. [verified]
pc Attacking Reilly in Underworld's hospital doesn't turn the civilians hostile. In fact, if she is awake when you attack her, civilians will help you kill her (seeing her as an enemy). If she is still in a coma when you kill her, you will take the regular Karma loss that would be incurred for killing an innocent, though civilians will still not become hostile. [verified]
xbox360 Reilly may be awake and hostile upon entering the Underworld Hospital. If you kill her, you will fail the quest and you will be unable to contact any of the other Rangers. [verified]
xbox360 Upon speaking to the rangers on the rooftop, Dogmeat may suddenly die. Reload a previous save and re-attempt to talk to the rangers to fix the problem. [verified]