You have picked a awsome cruise. I went in September and am planning on going again on it at the end of august.
We stayed at the Sheraton Old San Juan, it was $184 a night. It is right across from the terminal and you can walk around and see a lot of stuff.
Dominica we went with Fredos Peltier of Fredos tours. We went all over the place and into the rain forrest. Very interesting and he was $50 pp for the day. His webstie is: http://freddy536.tripod.com/index.html
Check him out.
In Barbados we went on a Cataram and is was so much fun. It was Tiami Catamaran and we booked it from the ship. It was $95 pp but taxi, breakfast, all drinks alcohol and non alcohol, and a very good buffet lunch was included. Even if your husband didn't want to snorkel I think he would still love this!
I'd like recommend in St Lucia Shal of Jungle Tours, this was in a open air land rover and it was a lot of fun. Again we went everywhere and saw some interesting things, like being in a active volcano. He was $90 pp and lunch at a nice place was included. His webstie is: www.jungletoursstlucia.com
I loved Antigua to!! We went ziplining @ $115 pp. Then we went to Dickerson Beach, it's a free beach and is beautiful. We paid $5 for a chair and were parked in front of Sandles resort. (can't go in there for drinks) but there is a restaurant you go thru to get to beach, they have the best pizza I have ever eaten!! I don't know if I was getting tired of the ships food or what, but I still dream about that pizza!! It was a little pricey, $14 for 4 slices but worth every penny. At this beach they have all sorts of stuff you can rent, boat, horses, etc. My next trip I will skip the ziplining and stay at this beach all day.
St Kitts wasn't a stop when we went but am looking forward to it on my next trip.
Wish I was going with you!! This has been my favorite cruise todate.
Oh yeah, you CAN buy booze at the terminal and take it on with you, can save you bunch of money there and also can take cokes and water. I didn't do it in San Juan but loaded up on cokes in St Thomas.