Well, we did it and it looks great! Was not as hard and I thought it would be although at first it was a little daunting. The worst part is the amount of rot there is on the back part of the rv. I'm guessing but it looks like the moisture has dripped nearly every morning from the top of the rv down the back corners and into the screw holes holding the moulding on?
We did mostly just like the mechanic described except that we couldn't find a piece of 1/8" plywood - so I bought a piece of 1/8' paneling and sanded the paper covering off of the one side leaving the porous wood.
The bad news is that we discovered the entire back part is delaminating as well - but if I tackle that job it's gonna have to wait until fall because the Texas sun is tiresome!
Unless you looked hard, you really can't tell where we worked on it. The laminate is a little "stretched" right at the point where we pulled it back as far as we needed but other than that, no bubbles or waves.
Tomorrow I'll re-caulk and hopefully we'll be done with that project for a while!