It gets real hot inside all RV's when parked outside for months at a time, resulting in shelf covering type stuff peeling off, often after the first summer.
over almost anything I always start out with a cost of KILZ primer/sealer and then apply quality latex of the desired color and finish.
Don't think that I have ever seen door hinges attached with rivets. Can you post a pic?
IMHO: "Quality Paint" and "Spray Can" are seldom found in the same sentence.
By "Quality" I mean that it will last at least 5 years.