Welcome! There are legions of Flying Cloud owners here... having had a couple of '53 FCs in my yard last summer, I can tell you that everything in them (except the
12v wiring) is bonehead simple and (relatively) easy to get to and repair or replace. They were built during a much simpler time using mostly apartment-sized appliances and standard plumbing fixtures.
There weren't any manuals for Airstreams until the early '70s.
Good luck, and be sure to post lots of photos!
Roger