Thx for all the advice I wil definately pick up that book. Also a big thx for the advice of the bulkhead material that is considerably less $$ which of course is always good. Do you think that wood is good for rebuilding the "Furniture" for the interior as long as I prep it like you mention. Also I was thinking of coating it in fiber and finishing it with white epoxy paint (marine grade) to decrease the maintenance of wood finishes in the long term and brighten up the cabin (and make cleanup easier). does this seem ok?
Marine grade plywood has 3 advantages over plain old exterior grade plywood. It is guaranteed to have no voids, its glue can withstand boiling for some specified period of time and it usually has pretty face veneers.
A few small internal voids or "boats" on the faces are no problem for construction inside a boat. Regular exterior ply uses waterproof glue that can withstand soaking - do you plan to boil your bulkheads?
You can cover the ply with any pretty surface you wish, just include their thickness when you choose your base plywood thickness.
I think you will find very little "marine" ply used in boat interiors. It is very desirable for building dinghys and so forth but simply added expense for what you are planning. at $hundreds a sheet compared to $10's a sheet, it's no choice at all to me.
An all glassed interior would require a lot of finishing work to smooth it out. If you want low maintenance, I'd use high pressure laminate (Arborite). You will be reducing the boats saleability though IMHO - people like wood on sailboats. I'd face things in teak or cherry veneer - something like that. It's not very expensive to do using 1/8" material.
Don't bother with "marine" paint inside. The high price is due to all the UV inhibitors, abrasion resistance and so forth which are not needed inside. Regular bathroom paint works very well - it has some mildewcides in it for damp environments. Use semi-gloss - it has a nicer sheen than gloss and hides problems better.
P.S. if you are determined to do a "glass" interior, use something like 10 oz. cloth, not biaxial or roving. 10oz. drapes and lays very well and if you heavily resinate it, requires minimal filling to bury the weave. The coarser fabrics are designed to build laminate thickness, not provide a fine finish.