San Juan is awsome. if you can spend some extra time in that port, Do!
The Rain forest is breathtaking and the rum factory is a must. Be sure to wear comforable walking shoes.
Save your spending money for the camera stores and Jewelry stores in St. Thomas. Never settle for their first price.
Coki beach is the best for experiencing a little of everything(beach,snorkel,jet ski rentals) at your own pace.
Aruba is better for the Sumarine excursion.
Enjoy!