Best way to seal roof?

I have a 1997 Xplorer. A few years ago I found a spider crack area and a deeper gouge on the roof. I covered both with eternabond tape. It's still there. These 2 areas were not leaking but I wanted to protect them. I have had leaks from under the gutters which cover the joint of the fiberglass roof and the metal sides. I've removed them twice and resealed. Eventually a leak started again. I covered the gutter with white duct tape and no more leak. I will do the whole of both gutters next. The rear window has 2 crews on the outside top hinge. This is the safety exit. The caulk wears off and they can leak. I recaulked, but then covered the whole hinge seam with matching black duct tape and no more leak.

Do not walk on the roof!