Since it would be impossible to survive as a regular human in the North East or the West of the US, the area should be around North Dekota/Texas or somewhere in the mid-US.
Survive against modern raiders, rebel military/robots, wild animals and basic life.
No mutants.
Vehicles still should work and houses still standing.
Be able to create colonies and recruit people on streets.
Storyline slowly progress from witnessing nukes explode far away from clouds, rush to vault-tech or your own bunker, rise up, no chaos on streets, little rebellion from teenagers and outside influences, chaoes increases outer town, complete chaos. At each step, resources reduce.
Your impact, prevent complete chaos, create chaos, create new governemnt, create colony.
Any more ideas.

I prefer the war to be more mysterious.... I wouldn't be as excited about a pre-war/war era Fallout game as I am for ones like FONV

I feel pretty much the same, it wouldn't feel like Fallout if it was done pre-Apocalypse.

I preefer to see pre-war as that "time before time" sort of setting for the Fallout Universe.

No, the setting works better because it's veiled in mystery.