Alan, I'm trying to remember... are the hinges like the ones Scamp
uses with the brass ball? And no, if its just the bottom of the door that's not fitting well, then replacing a hinge isn't going to help a whole lot. If the door is sagging from the top, then lifting it up may help the door fit better in the whole area, so then fixing the hinges is a good possibility.
Is it possible the bottom of the door is full of water? That seems to be a fairly common occurance in aircraft-style doors.
Just know it's very, very, very doubtful you'll ever find a new door to fit a 30 year old fiberglass trailer. So let's see what we can do to help you fix this one. I know your camera died, but please post pictures when you can.