I recently took a side trip to Crystal River. Its on the west coast, full of springs and the winter grounds for manatee. You can get a boat trip wiil get to swim with them, rent kayak gear and paddle bay, paddle and swim to mouth of springs, etc. Great little area and cost of a day with both the boat trip and kayaks will be far less than anything Orlando.
Sshh. Don't go telling everybody that. Lol.