Here are some more ideas: Antigua and St. Lucia are really beautiful islands and thus I suggest hopping in a cab to either the Rex St. Lucian hotel or Halcyon Cove Hotel in Antigua and enjoy the lovely beaches and watersports there. It'll save you lots of money compared to a purchased shore excursion and we LOVED these pretty beaches.
In St. Thomas, you may want to go on a purchased shore excursion to Trunk Bay in St. John. Gorgeous water and great snorkeling trail. Since you have to take a ferry and jeep to St. John, I'd suggest purchasing the excursion through the cruise line.
In my "Back to the Beach" article, I mention some beaches in St. Maarten that do not have nudity. (Avoid the French side of the island where nudity on beaches is more prevalent.)
Feel free to ask any add'l questions.
Luisa Frey Gaynor
Family Cruise Editor