Please be sure to check out our Caribbean Port Chat section a little further down the main page. You can use your "find" feature in the upper left hand corner and type in your ports, it will pull up all the posts made about them. You might find something that interests you.
St. Thomas-take the ferry then the bus to Trunk Bay. St. Croix-snorkeling/beach excursion. St. Kitts we've done some snorkeling excursions-not that great, the Batik factory was very interesting and the fort was a nice tour. Antigua there's 365 beaches, last time we were there, we hired a driver outside of the terminal. He took us to Shirley Heights, the dockyard, and to a beach. It was a great way to spend the day. St. Lucia-snorkeling, pitons, Pigeon Island.
Congratulations on your up-coming cruise! You have some excellent ports!