Fallout
GURPS Fallout
Radiation is considered an occasional hazard, not rare. See the Resistant advantage.
Templates
Technology
(Part of this is taken from Gurps_Fallout_compilation.pdf and http://fallout.wikia.com )
GURPS Fallout, like the Fallout computer game series, takes place in an alternate universe. This means that, sometime after World War II, real history and Fallout history diverged, although where this happened is not exactly clear. The alternate reality, henceforth referred to as the Fallout Universe,is awfully close to the real world, but with some major differences.
Player characters are set on TL 7 like most of the tools, weapons, armor etc. There are some high-tech gizmos available occasionally though TL 8 an onward are quite different from what's normally expected on regular Gurps worlds. This applies especially to medicines, chems and other consumables.
Also, being post apocalyptic scenario: Item availability depends a lot according the location and contacts. Poorest villages and Raider groups have at most some basic fire arms (badly maintained 100-200 years old TL 6 items), while some influential groups have nice shiny armors and well kept weapons (7+1 to 7+3) available strictly for their own members (=NPC).
Since most of the high tech gizmos are Pre-war made and extremely expensive, best bet for player characters finding these would be looting some Vault or other historical site before others do. Otoh, the vault's have strong doors and deferences so it's not going to be easy. Military outposts are best left alone since those are guarded by deadly automated defense systems.
For more details of equipment and pricing, see Fallout compilation pages 36-52.
Critters
TODO
World
TODO