You didn't say whether it's fiberglass or aluminum siding? If it's fiberglass and you have delamination on the trailer your getting a frame. Is the only thing rotted is the slideout? I purchased a late model project camper this winter. The camper had three holes in the roof from tree damage. I'm in the process of redecking the roof and putting in a new ceiling. Will redo the counter and put in single bowl deep sink. Then new carpet in the slideout.
If you have the skills these things are not rocket science to put together. The materials are not that expensive as well. The most expensive thing is labor. At that age it will need a new roof and probably decking. A RV repair center in Hutchison had three RV'S in their 8 bays for slideout repair, most late model.
While it takes very little time to build the RV it is very time consuming to repair. Another issue is do you have a dry space to work on the unit until it's weather tight? When you get done it will only have limited value because of it's age. As mentioned earlier the appliances will be at the end of their life cycle and can fail, water heater, A/C, refrigerator and can be expensive to replace.
You can have a lot of time in the RV that probably could earn enough money by working a job and purchasing a newer unit. I'm retired so my time is only of value to me. If I do a project it's during the off season's. I would rather work on something then sit on my posterior and watch tv.
Like I said earlier most projects people purchase are not completed, people lose interest. Good luck with your decision.
