Just an idea for when we get to Philly: as one of the few groups not to be seriously effected by the bombs, Amish have taken over, through cultural spread, not militarily, as they are pacifists. At least having Lancaster relatively untouched and the people still living relatively the same would be pretty cool. Kind of a commentary on how the technologically advanced people lost it all, when the backwards people survived.
Not sure how they'd survive raiders, though. Probably feed them, give them supplies, treat their wounds, and say goodbye.