Definitely have the Fallout setting take place in a big city. I like [@ActRaiserTheReturned]'s idea about Fallout Quebec. I don't know of any famous landmarks in Quebec, however (Only mentioning this because I know people at Bethesda Game Studios love to make their game more immersive by adding well known statues, buildings, areas etc,).About the faction idea, personally, I feel like it would be nice to have some cannon factions tossed in with some non-cannon ones, such as BoS and The Children of Atom.