One thing which has helped me in diagnosing leaks is to change the tilt of the trailer and see where the drips go under different states of level. For example, if the a/c is leaking to the rear wall, drop the tongue all the way down and see if the leak remains in the rear bath. With the A/C lower, the water will not run uphill to the rear end. A/C eliminated. This could be a lengthy post...
I hope you get my drift. You can eliminate some disassembly by methodically eliminating roof mounted items this way. Water will run all over the place, but it doesn't defy gravity, usually. (It can wick uphill, but that's pretty far down the probability list.)