We have sailed on the Island twice. The last time was about a year ago when we did the Panama Canal. Love the size of the ship and the cruise. First stop was Aruba and we were less than impressed. If you don't want to go to the beach for the day there wasn't much here. You will dock right down town so there is no walk to speak of. Cartagena we took a tour of the Old City and enjoyed that very much. In Limon we did a tour of a banana plantation and found that to be wonderful. In Ocho Rios you'll dock very close to town so we just walked in and had a nice time with that. We ended that visit with a wonderful margarieta at Jimmy Buffet's. The best time was the transit of the Panama Canal. You'll have to get up early as you'll enter about 5-6am but it will be worth it. Just to see how the locks work and the other huge ships that will be around you is terrific. Our balcony room was the last one, starboard side on Emerald deck. the balcony wrapped around so you had a wonderful view of everything. We were so close to the sides of the canal you could almost touch them. We are in our early 60's but there was every age group so I'm sure you'll feel comfortable. If you need any other info just let me know. Have a wonderful cruise.
Don't worry, there should be all ages on the Panama Canal cruises ('mature' fellow passengers are often very interesting with lots of different life experiences). We were on the Island Princess in Oct 2011 and we loved it.... and the ports as well. Even in Aruba, I enjoyed the snorkeling (husband remained on the boat). Cartagena, we walked out to the entrance into the cruise port, where there are several private tour operators wanting your business; do your homework as to what you want to see, take others with you as they like to fill their mini-vans, they'll take you where you want to go, but above all, don't pay the first asking price, haggle a bit! Our guy took us to an emerald business, which I now regret not buying in (I later found out they were very reasonable, as off the beaten tourist track, and a bona fide business), then he took us to the fortress and the old town where we walked around for 45 minutes, would have liked longer than that. As for the Canal itself, if you really want the full experience, take the excursion boat tour that leaves from Lake Gatun after your ship traverses the first few locks.... and go all the way through to the Pacific, then back to the ship by bus. We really enjoyed that! In Costa Rica we went on a privately arranged tour, John Joyner Tours.... he was very good, and took our minivan group up to the rainforest national park with an outstanding zip line.... 12 stations over the jungle canopy, it was breathtaking, a fabulous experience (and we are early 70's but obviously very active!!). In Jamaica, we did the ship excursion to the sugar plantation, lovely place, lovely lunch, peaceful but interesting and away from the crowds. It is near Falmouth, so a ways from Ocho Rios, but the drive gave us other perspectives on Jamaica also.....
Have fun! We plan to do this cruise again in a year or two, we liked it so much.