Any fix, plan on new carpet. I don't know if you'll find plans. I agree though, fix the boat! You'll need to remove all of the seats, side panels, and carpet.
Soft spots are probably one of two things. There is fiberglass over the plywood and it will delaminate on these older boats. Around 1998 Crownline went with XL treated plywood. I have a 1994 225CCR and had a soft spot just inside the cabin door. It was de-lamination. If it's a delaminated bubble, that will be a relatively easy fix.
Worse case is bad plywood. If you need to replace the plywood, my best suggestion would be to make a cardboard template before you take the floor out.
For what it's worth, I bought Teak/Holly veneered marine plywood for my cabin floor. It would look awesome in the cockpit if you could get a piece to fit. Google "Teak & Holly"
Gilly
1994 225CCR
TOBACCO Money