We have a Prowler 5th wheel about the same size and same age. Having this made my #1 point on a new TT that it be a Alum frame and as little wood as possible. When we pulled off the inside paneling, we found that the water had gotton into the batten insulation and soaked and rotted the 1X2 and 2X2 frame. The structure of the sides were worthless. It was easy to replace, because it was so rotten that you didn't have to cut thru the nails, they just pulled out of the wood. I found out the hard way that the roof is just 1/4" luan ply with a thin membrane on it. Honestly, the only thing keeping the whole front from falling it was the side walls. I rebuilt the whole front back to the bathroom. I'm about 300 lbs heavier because I used 2X4s instead of 2X2 and 1X2s and I used 3/4 water proof ply. I replaced the thin glass insulation with ridge 1.5" foam then used spray foam to seal all the seems and joints.
This is the 3rd wood frame RV I have had and the 3rd that I will scrap. I will never buy another wood frame RV and I would suggest you think about it before throwing away your money.