project pontoon camperboat (P.P.C.)

I bought what I've always wanted, a trailer able houseboat. The P.P.C. was started by the person, who sold it to the person, that sold it to me on Ebay. The seller told me it was "afloat at on time" tho it looks more like someone started to do what I wanna do, build a camper boat.
I am basically tearing it down as far as i have to at least the decking that is bolted to the pontoons.The pontoons are fiberglass, foam filled, 24" by 20' flat 6" flange at the top where they bolt to the deck that is 1" thick plywood, thats 8 1/2' beam 20' length. Pieces of I beam make the perimeter that has a 2"/4" inset around all but the rear of the boat where an aluminum transom bolts on to deck between the pontoons. Than a 2"/4" walled room built atop the deck, with fur out that over hangs the rear of the boat for generator, ac, stowage and such, also a small front deck 4' by beam.
The problems I see right off the bat are the overhanging stowage in the rear and the over hangs on both sides like the pontoons are to close, I would like to keep the pontoons as they are so I can keep trailer I will sacrifice beam width to keep the trailer if I have to.
I will take some better pics and more dimensions once i pic it up from lake Whitney Saturday the fourth. I would like to get it right on the first time with the Coast Guard when they do there test. I am asking for any in put and ideas the Y'all have being My first boat build I am going in as blind as one can be. I came across this forum while trying to find regulations on back yard built boats I found nothing on pontoons or house boat I could use a point in that direction also and if one is a coast guard and can help me figure out how to get her legal that would be the bestest. Reading thru hear I see Y'all are some smart people Ya may have to dumb it down a little for me. All responses appreciated Will answer any plumbing questons You can come up with in return. Thanks for reading and let the Redneck Yaht jokes begin.