Having been to Orlando as an adult, I would have loved to have gone as a kid. Never been to Disney, but with Epcot, Universal, Sea World, stuff on I-Drive, good cheap shopping, cheap food, it's a good place to go with something for everyone. It's hardly full of culture but from remembering my mates as a child who all went, there's always something for kids.
Sorry, no riding. But you can always get stuff sent to the hotel and shove it in your suitcase. A few years ago, I got some great riding type gear in a store in a mall. They sold Motox stuff like Fox etc. Got some gloves, shorts, decent riding shoes etc really cheap. Plus, if you buy the kids cheap decent clothes there, you'll have more money for bike stuff back home.