When I restored my Starcraft, I pulled the aluminum trim rail on the roof and sealed between the roof membrane to the framing, between the wall siding to the frame, and under the trim rail to the membrane. I used a good quality elastomeric caulk and didn't skimp on the quantity. I had leaks.
I then sealed from the roof membrane to the aluminum trim rail with Eternabond Webseal tape:
The Webseal tape requires a top coating to protect from UV deterioration but is easy to form over uneven surfaces. Since I planned to coat the total roof, this wasn't an issue.
Here is the finished roof:
I have done a few pressurized leak tests and the only areas that remained leak-free were those areas with Eternabond tape.
