Pat and Nancy,
I just came back from the W Carribean w/my kids. A good place in Cozumel would be Playa Mia Beach Club if you are in to the beach stuff. You can go on Shoretrips,com and buy an all incl pkg deal for $41 pp. That incl all your food,drink (even alcohol),chairs,a mini zoo,there is a water trampoline,and iceberg in the ocean that is good for the older kids. They even have life vests for the younger ones. My kids and ourselves had a blast there. If your not into the beach scene, go to Chankanaab Park for the day. You can swim with dolphins,or even just watch,and see sealion shows,etc. It is a beautiful place. Great for a family.