If you don't know what lurks under it, you could be just making more work down the road. Mold and rot aren't something to be sealed up and forgot about.
Delamination is mostly just cosmetic. It looks horrible but it is not the end of the world either as long as you figure out what caused it. At times, it is easier to work on the inside and pull panels/insulation rather than attack it from outside. This will give you an "easy" button up job on it and also to see if it was water damage or glue failure.
And grit is right, if you are looking at a damaged rv and it's not REAL cheap or your a wizz kid at fixing things...run away!