T.O.
We just took a great vacation with our 2 kids (ages 2 & 5) to Captiva Island, Florida. It is on the Gulf of Mexico about 40 minutes from Fort Meyers. We had a great time and the resort we stayed at was amazing! It was so kid friendly, yet we enjoyed it as adults too. Oh and I was 6 months pregnant at the time and still found it to be so relaxing and fun.
Check out this website: www.southseas.com
This is the resort that we stayed at. We stayed in one of the Gulf Beach Villa's (facing the Gulf of Mexico and just steps from the beach). There are several pools that you can choose from that are zero entry and there are some fun pizza and ice cream places that our kids enjoyed a lot. The resort was very clean, up to date (due to Hurricane Charlie) and very friendly staff everywhere. Best of all, the flight was easy....3 hours from Minneapolis to Fort Meyers and then just a short drive to the island.
Good luck in your search!!!