Serious delamination is USUALLY the result of a serious leak. I would get rid of that coach since there is a good chance that the roof, floor and interior wall has moisture damage and may already have a mold problem.
Once you start repairs, there is almost no turning back. It could become a money pit and the cost of the repairs will almost surely exceed the value of the coach. Getting rid of it now may provide some sales/trade in positive value but once you start repairing it you could easily go in to the negative value.