[and then some]

Hi! As you can see I'm new to this forum. I'll start with a little back ground. I have a 20' CC 1970 something. Mom wasn't sure when dad bought it. It's been totally gutted. All wiring and controls are gone. The transom is rotted. Floor is soft in spots. I've pulled the gas tank and drained it. It seems to be sound but I'll pressure test to be sure. The floor under the tank was soft so I cut a chunk out and the wood was wet but solid. I'm thinking of using composite for the transom but would like your opinion. I've done a lot of checking into seacast and even have a sample. It seems to be a solid product with a solid company. The sample arrived 2 days after I e-mailed them the request. After looking at all the posts on tramsom rebuilds I've decided to go in from the inside. But where do I start the first cut? I'm thinking of starting on the lower vertical front of the bilge access compartments and running up the sides and removing the back 3' of the inner shell. How does that sound? Sorry this is so long but ya gatta start some where. Thanks.