If anything, make the map bigger...
Ya, at LEAST twice as big, if not global (using players from local areas to at leat design them).
Also if it would be me, I'd scrap the fo2 part of the map.
and ... we could play before the begin of Fallout1 , with the master planning, or few months after
... revert back about 100 years.Change every single NPCs dialog.Replace 70% of the scenery and delete half the map.