Re: Generation Ship Campaigns
I assume that you've read Robert Heinlein's novella, Orphans in the Sky (or is it Orphans of the Sky?). Multigeneration ship has a mutiny n generations into the trip, all officers are killed, radiation is released on certain decks of the ship. After many more generations, the humans in the outer/lower decks have reverted to peasants run by a religious class who control the power, access to information, etc. The inner/upper decks are controlled by mutant groups who kill any pure humans who venture that far. Everyone forgets they're on a ship.
Anyway, you could get some very good ideas from that book.
Hope that helps