Delam is almost always caused by water intrusion of some sort. Pictures of the situation will helps us comment.
I had to perform extensive repairs to a filon sided camper years ago and as you allude, it is not fun. It is not that it can't be done, but it might end up to be more than you think.
I am not trying to sound pessimistic but there are folks here who do as a hobby of sorts and anticipate it as a challenge. If you opt to take on this repair, my advice is to see it through, keep a positive attitude, it can get discouraging if new surprises appear. In the end it will be something to be proud of. I did similar on a previous TC and almost gave up but I got 'er done. I will not do it again.
