I recently joined netflix.ca (horrible selection) and found an awesome post apocalypse TV show that i quickly fell in love with. The 100!
An interesting take on the post apocalypse.
What if survivors fled civilization before the bombs fell. They headed up into the uninhabited wilds (forested regions away from civilization). What if guns didn't survive the end of the world? What if the survivors devolved socially into a tribal savage society. One which uses bows and arrows, melee weapons, wood furs and leathers as well as any remnants of the old world they could get their hands on? (In the 100 its in the general area of washington DC almost 4 generations after the fall of civilization).
Its the same idea as Native Americans meets European settlers. Except in the show the settlers are from the 12 space stations in orbit. (tethered together to form the ARK). The big bad guy in season 1 is an invading army of savages against the juvenile prisoners, the 100 as well as basic survival against a world they know nothing about. In season 2 it is the Mountain Men. Survivors who live within a nuclear hardened underground bunker.
One of the most interesting concepts i've seen so far is how the show handles radiation.
(Spoiler Alert: The entire world is heavily irradiated. Like a normal human will fry in under 30 seconds of exposure.)
The above ground survivors are immune to radiation (man made radiation).
But the survivors from the ARK have a stronger immunity then the savages because they were exposed for nearly 4 generations to unshielded solar radiation.
(I thought that was an awesome take on the radiation concept.)
I could see a spin off of this in the fallout universe.
Keep all the tribal stuff. (a romancable female tribal leader would be awesome! Love that character from the TV show.) Instead of survivors from space stations, use a vault. Main character is ejected, exiled or is forced to leave for whatever reason. The big bad guy would eventually be the enclave. Your character has the knowledge of the past. So guns are familiar to you. But extremely rare. Until the enclave reveals itself. Power armor is acquired in a later storyline event. Farther into the campaign. (Not common that far away from civilization. And it would make you a god against the tribals.)
Your character, no longer having access to your vault is forced to become a little savage. Become a warrior. But could have other career professions. Medicine, engineering etc.
Later in the story your forced to return to your vault to save your people "Clan" from the Enclave, reuniting with friends and family. The enclave is the sworn enemy of the tribals which force the vault dwellers above ground to survive.
Might also be a good time for a Poster Girl (female Main character). Which i don't think bethesda has ever done. Sure you can make female characters. But they've never made a Poster girl before, always a poster boy. (What? I like strong female leads).