Most manuals that came with travel trailers back in the day were sales brochures and fairly generic. You may be able to find printed appliance manuals but those are typically available online.
You can look in the restoration thread in my signature line, "the Cowboy/Hilton" to see how I restored a '72 Starcraft. Typically, restoration of anything in that age range involves a lot of work as owners typically lose interest in upkeep and the consequent water intrusion will mean framing repair.
You tube video of '72 Lancer