I've been playing a lot of Fallout 4 recently and really would love to actually interact with real people instead of the buggy AI in that game. So close yet so far...
So yeah, future post apocalyptic. Maybe not so much the atompunk theme but some of those songs are pretty damn catchy. End of the World, Atom Bomb Baby...
But when you say RPG, I hope you mean an actual roleplay and not one of those stupid things where there's a completely add-on driven system and nobody's ever online and you die for stupid reasons or have a uniform (I hate those City RPG servers with the stupid bald people everywhere) or some crap.