A.B.
We took a cruise a few weeks ago and it was really great! You can get in on some of the cruises at really great prices, but my guess is that they'll be busy over Spring Break. We went with Royal Caribbean, and they have great programs for kids 3 and up. There isn't much for kids under that age.
We also went and stayed at the Iberostar resort in Cozumel a few years ago. This would be a great place for kids... because there's the beach, the pool, and they have a kids club where they do a lot of neat things. It's all inclusive... and the food is incredible!! You can fly sraight on to the Island, so that's nice. A resort might still have some "Spring-Breakers"... but my guess is that it will be more family oriented.