We loved our tour with Sunny Liston tours in St. Thomas. He was a blast and gave a good tour of the island. We also enjoyed our tour over to St. John. If you go to St. John, I would recommend taking the boat from Down town and not from Red Hook. The ride over to and back to Red Hook is LONG. I'd rather take a longer boat ride.
In St. Maarten, we took a cab over to Maho Beach to the Sun Set Beach bar. It is at the end of an airpot run way and you can watch planes come in while having a "beverage" and a bite to eat. There is also a small beach there if you want to catch some sun. We had so much fun there!