Maybe they're people looking for a new home? Running from something or someone?
There were good people in The Road, although in the book I remember reading about towns with people in them, and they were forging weapons or something like that, but I don't know if they were good or not. Maybe it wasn't the end of the world, just the end of civilisation and the opening to a new, terrifying chapter of human history? (Little reference to Fallout there!)