drsteve wrote:
What everyone else said. Run.
From the pic, the entire back wall is shot. That's a big gap at the top, you can bet many gallons of water have made their way into the trailer. So the floor may have issues too.
Unless you have the tools, the skills, and a place to tear it apart, you will pay thousands to have someone repair it.
.... If it's even repairable. Looks to me like serious delamination besides the rot you cannot see (until you tear it apart). All could have been avoided with proper maintenance, something that many RV'ers don't even think about.
if you can get it dirt cheap and have the necessary skills and a ton of time to repair it, maybe but if you have any doubts, look elsewhere. That could turn into a nightmare.
Probably best to landfill it (after selling all the appliances inside).