Glue or Not?

[mfkaplan]

I bought a teardrop that while sturdily built, needs some refurbishing. The builder did a spartan job just to pull it up the Alcan. I chickened out on building one from scratch. I just finished the galley by replacing the ugly flooring linoleum lining the whole inside with oak ply and molding. I used brads and Gorilla Glue to fasten it. Gorrilla Glue is not my friend! Took forever to get off my hands. I am using several coats of spar varnish on the galley and the sides. I also want to insulate the inside and line it with 1/8 birch ply.
This is my question.The outside sides are covered with a rather lumpy fiberglass job. The top is smooth. There are horizontal cracks in the finish on the sides so it has to be fixed. At this time. I don't know if perhaps the bulider used plywood that had one good side (the inside) and one rough side (the outside), or just did a bad fiberglass job. I can only find fiberglass mesh on the corners. I plan on sanding and filling the sides untill they are smooth. I want to make it a woody by attaching 1/8 ply to the sides and then trimming the outlines with 1/2inch lumber. I know I will be using brads to fasten it down. Should I use any type of glue. Liquid nails? How do I prevent water from getting between the sides and the skin. Silicone Seal? I don't really want to use aluminum Trim. The top will be painted to match my PT with oil base enamel.
Mary in Central California