to FiberglassRV, we're glad you're here
BEFORE you start tearing into anything, especially the wallcovering and insulation be certain to find out what it's going to cost to replace it. THAT alone may stop you in your tracks. Ryan replaced the ensolite in a Trillium
Sportsman and it cost him >$1,500 and he did the work himself. There are less expensive solutions AND more expensive solutions, but none are easy to put up.
Remember, it doesn't need to be perfect, just perfect for you!