Hi Elaine!
Thank you for visiting the Moms Panel!
I think Typhoon Lagoon would be your best choice, with plenty to entertain a six-year old.
At Castaway Creek, the 2100 foot circular river, you can all enjoy floating along through a rainforest, and caves and grottos.
For your six-year-old there is also plenty of enjoyment to be had at this water park. Ketchakiddee Creek has everything for little ones to enjoy - slides, fountains, waterfalls, mini-rapids and much more, all in a safe environment.
Full details of all the attractions at Typhoon Lagoon can be found
here.
If you have any other questions, please come back and ask me - I would be happy to help you plan your magical vacation!