Wish we were going back on the Victory, think you are talking about the cruise that leaves out of San Juan and goes to the Southern caribbean? I have done this itinerary 3 times with a few port changes over the years and it is one of my favorites. If you are and your staying over in San Juan take one of the shuttles (buses) there free and they stop at most corners where you can get off and catch another, it's a great way to see some of the area including old San Juan, the castle and the oldest spanish fort.
As far as excursions, if it is going to Domincica, if you like really physical excursions I would recommend the river hike to Sari-Sari Falls. It was absolutely beautiful and a real work out. The only thing I didn't care for quite so much was the bus ride that was about an hour each way.
If Barbados is on your itinerary, I loved the Zipline it was the best and safest zipline I have ever done in the Caribbean. Another excursion that was really interesting and great if it is raining is the Harrison Caves. Hope these help