Saber4mike, can you stick your head or a camera through the forward sole access panel? Pop some pics. (I did and the stringers are quite near under the plywood.) Climb down into the ER, grovel forward, and you should see the aft end of that forward cabin. With luck, you'll see the edge of the sole plywood. Our 84 Europa is probably pretty similar, but as noted, there's apparently lots of variation in these TTs.
Lazy being good, I'd bet that the forward plywood subfloor / sole went down on the stringers and on blocking at the right height where it meets the hull. That would be as low as the fiberglass structure would allow, it would be an easy first step, and a platform for the workers to work off of. There would be no plywood where they did not need it. (That said, our old sailboat's bulkheads went in before the soles, but there is no subfloor.)
It's probably reasonable to believe that the interior finish work was started from the bow. Thus the last thing to go in would be the bulkhead between the lower, forward cabins and the main cabin. In our boat, the sole in the head is separate and in several different levels and pieces, and I'll bet there's nothing under the bathtub. Some of the cabinetwork would have been preassembled in the shop and brought to the boat in chunks; you may be able to figure out how it was done and remove it in the same chunks.
You may be able to Sawzall out sections in such a way that you could replace sections as you go. You may be able to take out, say, the 3/4" plywood subfloor and replace it with two thicknesses of 3/8" plywood strips with the joints staggered. That way, perhaps the bulkheads can be maintained in place.
Pics! And good luck!
