sorry i was not able to chime in before your cruise - i only joined cruisemates recently.
did you find some good excursions?
grand cayman - loved sting ray city and loved the turtle farm
cartegena, columbia - at the time we went many years ago, we were told to be on the cautious side. we just stuck with the ship's bus tour. i remember just loving the streets and buildings. had that old style, soaked with history feel to it.
cozumel, mexico - i've been to cozumel for a week's stay when i was younger and loved scuba diving there! 200 ft visibility - it truly is a paradise for any divers. but if you are not certified then check out any type of snorkeling excursions from the ship. last time i went, i was pregnant and was not allowed to scuba dive so we went on this snorkeling trip through a marine conservation area. very, very cool!