Trailor restoration.
Please take the time to look under off topic.You will see pictures and descriptions of our 1990 25ft. Classic restoration.I can't help you with the roof question because we didn't have any dammage on our roof. Our roof is rubber. All roofs need to be sealed with the appropriate primmer and roof seal. You would fix your roof first. Look up posts by Jcurtis on his alum. roof repair. The long story short is your trailer is very fixable if you want to spend many hrs. and about $1000.00 on materials. Lets talk walls,we only tore out two walls to the fiberglass. In these areas I used 3m Bondo to seal the walls.You will follow all directions on the can. You may well have many pinpoint holes in the fiberglass that you can't see. Then we used 1" styrofoam sheets to fill the cavities between the metal studs. Our glue we used was Heavy duty Liquid Nails. Glue the styrofoam to the fiberglass. Then we used 1/8inch underlay. The underlay was stained/both sides. Some have used waterproofer or polyurethane on the underlay. Some have used generous amts. of contact cement. This could depend on the time of year you are doing this. Be extremely generous in the amt. of HD liquid nails that you use. We used a $35.00 floor roller to press each layer to the wall. Then we applied 1/8Georgia Pacific paneling that had vinyl on one side. Some have considered renting a machine that will spray icine insulation in the wall cavities or get a co. to do it for you. Also consider using house wrap/thin vapor barrier in place of the rotted brown soggy paper that you tore out. Some have welded in more metal suports or put strips of wood in the wall for support. Use Lexell caulk and spray foam insulation any place you can. We had rainy days after we had used the bondo and had drops that water that we had to do more caulking or foam spray. You will certainly be able to improve some from the original . Better materials are now available ,butyl tape and Lexell caulk. All of your windows must be taken out and resealed. This is a do it yourself job. Need a helper. I,m trying not to over whelm you with details. We are all here to support you as you bring your HiLo back to life. Plenty of us have done these types of restorations /repairs. Let me know what you think after you have read my restoration story.