I couldn't say due to year, but I would be surprised if wires were run thru ceiling, waiting to fix wiring when doing roof only to find you cant, my cause for comment. Though certainly be easy to run new wires for that section of circuit. Wires in ours run behind cabinets etc there is very little if any in exterior walls (excluding running lights), with main bundle running on left side, bundle running to right side crosses behind water tank. Only 12v wires in ceiling go to something in ceiling. But bath fan/light is fed from wall, then goes back down to switch, where porch light is fed, wire going up to it from switch, only wire I'm aware of in exterior wall. What wires were in ceiling were continuous-no junctions except right at fixture. Again though, doesn't mean yours don't and probably is completely different.
When checking switches-none of mine, or fixtures, pass power. So a bad switch would only affect its output but nothing down stream. One of my pet peaves on our camper, juntions are made outside (behind) switch/fixture.
Where daisy chained or continues downstream there will be a crimped on wire connector with a drop/branch for that switch/fixture. IE main wire is cut then it with branch wire is wire nutted. Ground is same. Not the connection of fixture/feed wires to branch wire but branch to main. Only end of line is directly connected to something. So when checking-gently try to pull wire untill you find its (if) crimped on connector, I suspect branch connection.
As to fleetwood TCs-Id buy another tommorrow if they still made them-however I wouldnt buy one if they started making them again. Specificaly due to thier complete cut off of support for TCs when they stopped making them.