We opted to take a taxi to the Marriott St. Kitts to use their facilities. We didn't know if would cost $35/person which included towel, chair, umbrella, but glad we saw the property. St. Kitts has a nice little shopping area by the ship and we would like to return there for a longer stay.
We love St. Thomas and not only like to cruise there but also like to stay for extended times. There is so much to do between there and St. John, you could never get bored. Charlotte Amalie can get very crowded, especially when there are several large ships in port which can be overwhelming.