Have any of you guys ever watched Jeremiah or Falling Skies? In both of those shows they travel a lot from one area to another among decaying ruins of the city and so on. Jeremiah I honestly think is the closest TV show so far to Fallout as it had similar plots such as a vault-esque area "thunder mountain" and factions like the valhalla sector that were sort like the enclave.
Creating a fallout style/post-apocalyptic show is all about the atmosphere of the sets. That can be done on a TV show budget, as I mentioned with Jeremiah.