Thank you, everyone, for the great ideas. I have a nice list to take with me.
I already took a couple people's advice about the shuttle vs. renting a car. I decided to rent a car even though it's costing me $80 more than the shuttle (then gas on top of that), but since we aren't able to stay very long I decided that we would be able to visit more of the area with a car. Plus, the trip to and from Orlando should be quicker with a car.