I restored my Starcraft by removing the inside panels and fixtures. I removed all rotten wood and replaced with new. I also insulated and wired everything while it was a shell. If you have a plywood-sheeted roof, you will need to remove the roof membrane so that you can repair that sheeting.
The Starcraft renovation costs were around $4K and the labor (my own) was around 6 mos. of almost full-time hours.
The good news is that I now have a trailer that is easy to heat/cool, is comfortable, and the inside is laid out exactly how I want it. Repair or renovation is possible and one doesn't need to be extremely skilled to accomplish it. The purpose and intention of the repair has to be weighed against the result and situation of the owner.