Without going into a lot of detail, these are the excursions we took (all through Princess) and thoroughly enjoyed all of them:
Huatulco - "Huatulco by Land & Sea;" Huatulco is a beautiful and well planned resort, not unlike Ixtapa. This tour lets you see its many beautiful bays and resorts from a large catamaran, with very knowledgeable guides and refreshments; then an air-conditioned coach tour of the local countryside, with plenty of time for shopping (of course).
Puerto Quetzal - "Filadelfia Coffee Estate & Colonial Antigua with Lunch;" a beautiful ride with vistas of volcanoes, over great roads to Antigua; then a tour of a working coffe estate, and one of the best meals of the cruise.
Puerto Cortino - We traveled Westbound and stopped at San Juan del Sur instead of Puerto Cortino. We took a tour to Colonial Granada and Lake Nicaragua and loved it, although it was a long ride over terrible roads. I don't know what is offered from Puerto Cortino.
Puntarenas - We have been to Puntarenas twice; once, we took the tour into San Jose; a long ride, but a great way to see the beautiful countryside. Our last trip we took the "Tropical Train Ride & Mangrove Nature Cruise", which I can only describe as like the Jungle Cruise at Disneyland, except everything is real!
Cartegena - We have done the "Best of " tour and the "Old City Walking Tour"; both were great, but it was really hot and humid both times we were there; dress comfortably.
Aruba - "Aruba by Land and Sea;" It was our first visit too, and thought this was good way to see a lot of the island. We even had time for a swim in the beautiful blue water.
Hope this helps a little.
Have a great cruise. This was one (actually 2) of our favorites.