Yes! Best piece of advice. . . bring a blow up beach ball. Our kids had a great time not just on
Castaway Cay with it, but it was a fun diversion in our stateroom as well. Also, take advantage of room service--- it is super helpful, especially if you will be taking advantage of Flounders during the meals. This way you don't have to balance your toddler and her tray going through Topsiders. They can deliver chicken fingers, PB&J, hamburgers, salads, cheeses, etc.
Also, for breakfast, I always woke up early and enjoyed taking a book up to Topsiders on my own. Then I would bring down a breakfast tray for our kids--- cereals (they aren't normally allowed to eat Fruit Loops, but hey its vacation), pastries, bananas, bagels, yogurt, etc. Then DH could go up and have a quiet breakfast too while the kids ate and I got them dressed for the day. The kids liked the one day we did a sit down lunch at Lumiere's on a sea day because we got a table right next to a porthole--- they loved looking out the window!!!
Also, embarkation day with little ones is tough. This is especially because you have the crowds at the buffet so you are doing that tray/toddler balance in an unfamiliar place. The worst part is the safety drill when everyone-- including infants and toddlers--- must wear the life jackets. Trust me-- it is hard to carry a toddler in a life jacket when you are also wearing one!!! Just tell yourself all of these things are over by 4:30pm, and then you will be set to enjoy the cruise. Our first cruise we were really worried about things during these challenges but once it is all done you are all set.
Flounders is FANTASTIC!!!!!