Deck to stringers conection

[Cheg]

Just went through the same process. Moisture only in the bottom inch or less. Went back and forth about removal. Then one day while sitting there staring at it, I just grabbed a 2" hole saw opened up some square holes about 8" x 8" in the top and dug it out. Most was small enough to shop vac out. Took about 5 hours but it's done and I,m glad I did it. Mine's a 23' but still don't think you would have to cut the entire top off on yours. Made it easy to recover with fiberglass after it was refoamed. I'm less than 10 mins up the road if you want to take a look.