It's your coach and you can do what you want, obviously. However, I agree with Kurt. But if you aren't going to go with replacing the vinyl, it sounds like Jeremy has some good tips. Personally, as a collector, I'd never touch a used coach with bedliner, it looks awful imo. If anything, give it a smooth paint job on the roof.
I just thought about something. If you remove that trim around the windshield. Make sure you use the tool made for releasing the clips. You can get the tool from most of any auto parts store for under $10. You will damage your stainless if you pull on it. That is the one area I would suggest pulling the trim. Generally you will find steel and fiberglass coming together at that point. If there is any rust, brush a little POR15 on the surface. Its about the easiest way to treat it without yanking the windshield and grinding. I have had pretty good results with that stuff. The cheaper stuff you get from places like AutoZone don't really hold the test of time.
I have a guy down the street l know that does auto glass so that's not a problem.