I don't know which ports you will be going to, but probably include Cozumel and Grand Cayman. If you are really interested in Mayan ruins, a cruise including Belize or Progreso would be helpful, as they have the best ruins which don't involve a whole day of travel. The ruins in Tulum are also a great experience, and if you see them from your stop in Cozumel, they will involve a 7-hour day, as well as a very fast, bumpy high speed ferry ride over to the mainland. Grand Cayman has the not-to-be-missed Stingray City, as well as great watersports.
We are doing the western carib with Princess this summer, to Cozumel, Grand Cayman and Jamaica. Jamaica was the one port I had no interest in visiting, but since we're going, we booked an organized tour to Dunn's River Falls and around the island.
Whatever you decide, enjoy!