Meh. Just get some friends to join you, and go and do it.
RP wise, as far as how you'd interact with people ingame, you'd just be random Frelancers.
Your RP would reveal next to nothing of the story, for the most part, and even then you'd use your cover story rather than the truth.
It could be quite intersting, as your group of survivors attempt to build up what they can manage to get and figure out what they can actualy do, and what they want to do.