There's a bunch of places all over Central Florida (it's horse country!), but two that I have done: Florida Horseback Trail Rides (Cocoa) and Forever Florida (St. Cloud). I preferred the one in Cocoa. Forever Florida is beautiful and feels more like a tourist destination, whereas the one in Cocoa is done at the owner's home/ranch. Forever Florida is a walking tour, so the focus is more on the scenery. At Florida Horseback Trail Rides, you walk, trot, and canter, which is a lot of fun, especially if you're a more experienced rider.