Having investigated your make and model of boat and listening to what you want to do, I'd recommend the following.
Cut the cap as shown...
This will allow enuf work room to replace the transom.
Cut the deck as close to the hull sides as possible. You'll tab the New Deck to the hull sides and the smallest gap is best.
For a 25footer I'd use two Pieces of 3/4" ext. Grade plywood to fabricate the stringers and transom.
My guesstimate for Glassin' supplies is...
25yds of 1708 or1808 biaxial fabric.
25 gallons of Polyester Laminating resin with hardener.
5-10 yrds of 1.5oz CSM
4 gallons of Cabosil
4 lbs of 1/4" chopped strand
Lots of 1 qt plastic containers.
Lots of Cheap Chip brushes
4" bubble roller
Lots of 4-6" short nap paint rollers and handle.
5 Gallons of Acetone.
There's probably more but this is a good start.
I'd buy a Poly Tank.
Just an Old Dumb Okies Opinion!!!