Transom starting to go. Looking for advice

[Blue_Heron]

Is there any good way to inspect the stringers without taking out the floor?

If you're concerned the stringers are suffering the same fate as the transom, then you can stop worrying. Seacraft used fiberglass box stringers that don't have wood cores. If you want to inspect for some other reason, a good starting point would be to remove the deck over the fuel tank, assuming you have one.
Dave