


Best advice if you really wanna see whats in the safehouses, start a new game, use one of the xp glitches so you dont feel like you wasted a ton of time leveling a new character all over again, anyway, before you go to the tops, get friendly and do side quests for either the legion or the NCR (do the group you plan to betray or kill off first) since this will usually get you into to trouble with the opposing group, once you get your key, enter the tops confront benny, let the story play out however you choose, kill him, convince him to run whatever, after that is done your negative standing with NCR and/or The Legion will have been forgiven you will have neutral ratings.

No one is carrying the Keys for those locations, they just give them to you after completing certain quests, and I do believe you need to be on good terms with them which is usually the result of doing their side quests.
