Wisconsin. Sadly in WI photospheres and potatoes are unavoidable unless you cut most of the state out. I tried making sure that at least potato cams still have legible clues and photospheres are unique landmarks and don't have false GPS data.
Places featured in the Fallout: New Vegas game, also a very few places mentioned in the Honest Hearts DLC.
Other DLC is not in here because it all takes place in imaginary facilities that aren't there in the real world.