I see your cruise is over, but for anyone else going you can take a taxi from the port and do well in St. Thomas and Nassau, but in St Maaten I suggest an excursion from your ship there. We walked off our boat & walked to the beach, got a drink and a umbrella and chair. Sat down and it was fun, but the vendors started coming around then the people started coming over from their ships on boats. It got crowded after awhile, so we walked behind the beach to the shopping area. It was quaint and fun, but the people around the beach just didn't seem trustworthy. If we ever go back we will do an excursion.
Study where you are going, very important! Like St. Thomas, we took a van with others to a nice beach to snorkel (we were the only ones who got out at this beach) that was part of a resort, and took another taxi, by ourselves, to tour St. Thomas. I will never take another mountain tour though, that cured me of doing that. Those aren't even hair pin curves, I don't know how people did it who rented cars or other motor vehicles. He was a great driver, but you had to take turns going around corners.
Nassau we took a van, with others, to Atlantis resort and had a private tour of that.