It is always amazing how a little leak, or it's no longer leaking, turns out to be a very large problem. Fortunately, we knew this going in. Spent the last three days ripping out rotted wood and soaking wet plywood that has delaminated.
Started off peeling and scraping the plywood from the over-head bunk. These RV's are constucted like an Oreo cookie. A layer of styrofoam is sandwiched between two layers of plywood. Like a hollow core door, this construction is amazingly strong. A stiff putty knife and a small hammer to "carve" the plywood from the styrofoam seems to be the best way to remove it. Although the plywood glue itself has long since lost it's holding power, the glue bond between the styrofoam and the bottom plywood layer is still very strong.
After removing the bottom, we remove the rest of the interior plywood from the sides and front. I'm now ready to tackle opening up the seam between the front fiberglass shell and the roof itself. A pair of linesmen pliers, hammer, stiff putty knife, razor knife, cordless drill with a square bit, and a lot of patience go along way.