Does the camper have aluminum siding or is it fiberglass siding? The aluminum sides campers are easier to take apart and fix. I have done several now for myself and others. I'm on my 6th one now... I even own 2 project campers plus the good big one in my sig. The project campers were wet campers and I knew what I was getting into but the inside was in very good shape. You fix this from the outside in. Meaning take the siding off and or lift up the roof. Fix all the rot, use Rot Dr. CPES resin to kill all the dry rot fungus and then replace and repair any damaged wood. The wallboard can sometimes be saved by the CPES as it stiffens it, again from the outside. Then put it back together.
If you have common wood tools and a quantity of your time, this is something that you could repair. Not to scare you... Here is my sons camper. It is now better than new. Around $765 in parts cost plus 268 labor hours. We work cheap... Entire front wall, entire new roof and entire rear wall and corners.
A Winter Project - Roof Repair (Picture heavy)Here is Project camper no 1 taken apart. Have not made it to putting it back together yet.
2004 T1950 Restoration Project - (Ugly Picture Heavy)And Project camper no 2. I just finished this enough my kids took it last weekend. I have to post all the fixed pics but it may help you on yours.
2004 T2475 Repair - Project Camper No 2
You know the camper, you kept it up all this time, you like it. Yes it has a water issue. If you can get past the time it will take to fix it, you are left with a camper that could be better than new. Trust me, I have many friends who bought brand new campers and the warranty repair calls have been staggering... It helps tell me to keep maintaining the big one I have now in my sig. It is 14 years old, was paid for the day I bought it, and still is in great shape as I keep after it, all the time. How much you pay for a new camper now a days does not mean the more you pay the better they are built. It's sad, really sad folks have so many issues with brand new campers in this day and age.
Hope this helps and good luck.
John
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.