[bigeasy1]

Rod,as you know,I have the same exact boat as you do.
You can leave the rear of the inner liner intact,but it's one heck of a lot easier to remove the rotted transom core and the inner transom skin if you cut out the rear liner that has the lip for the motor box on it.
I removed the rub rail up forward of the hawse pipes made a cut on each side on the gunwhales right at the middle of the hawse pipe openings,and lifted off the rear cap.
I then cut the inner rear panel about 3"inches from each side down to the deck and across the bottom to the lip on the motor box opening.
This leaves the transom wide open making the transom core removal a whole lot easier.

Don't be afraid,you're going to have to lay up glass where you make the cuts on the gunwhales anyway,so what's a little more lay up and fairing.
Also it's going to be easier to tie in the stringers back to the new transom,and who knows what else you will find.You could have rotted engine beds as well.C'mon go ahead, cut out the rear liner panel,it only hurts for a minute,you'll be glad you did once you start digging out that peat moss with nothing in the way.

I don't see any activity from you on gla,I miss your posts and replies.That site's not the same anymore,it's gone downhill.
Keep us posted on the progress.If you give me a call,I can set you up with a great supplier for all your needs.You'll want to use a stitchmat if you're going to use epoxy.
Regular mat has binders in it to hold all those fibers in place,and epoxy doesn't dissolve the binder so it is difficult to wet out the material,it works best with a resin contining styrene(polyester vinylester etc),the styrene dissolves the binder.
Stitchmat like a 1708 has mat on one side and a woven double bias cloth on the other side,and it's held together with stitching (no binders).The epoxy wets that out nicely.Also because its stitched, double bias construction, it makes it easier to tuck into tight spots and drapes and folds very well.It is a very good structural material as well.