On AOS 9/14 we did Captain Nautica Power Raft on St. Thomas and it was great. The stop at Honeymoon Beach , St. Johns was some of the best snorkeling we have done. Like being in an aquarium there were so many fish there.
Definately book Eli's Eco Tour on Antigua it was great and a nice way to get a water tour of the island. Probably the highlight of our cruise tours.
St Lucia was tough we ended up at Pigeon Island a national park with a very nice beach and some great views from Ft Rodney. Cost was $25 taxi each way and $5 each for the park.
We used Glory tours on Barbados you may want to check them out although there seemed to be several alternatives if you wanted a water tour. We did a land tour there that was great.
Just go to a beach in St Marteen and have a blast.