Are you limiting your search to Florida? We've been there several times, but more for the beaches and Orlando parks than for anything truly educational for that age. If that's where you want to go, I'm sure others can lead you through the wonderful places to visit there.
We're now Northern Californians, and there is so much to enjoy in terms of nature vacations here. We're taking a homeschool "education" vacation with our boys through the Redwoods next month. Tahoe and Yellowstone are beautiful, and Monterey has a world-class aquarium (complete with many homeschool days if you time your vacation right). The gold rush started in Placerville, between Tahoe and Sacramento, and the Pony Express ended in Folsom (also just outside Sacramento). Sacramento still has "Old Town," which is the complete replica of the original town in existence during that time. Again, it's another homeschoolers' paradise for this age group. The "missions trips" down the coast are very popular for the 4th graders studying American history. There are lots of museums throughout the Bay area, too. Best of all, this entire area is scenic enough to make a beautiful relaxing vacation for all the adults tagging along on the educational journey, too.
