Lots of shopping on I-drive; check out Mall at Milennia and Florida Mall (both 20 minutes away from I-drive).
Also check out the smaller attractions on I-drive such as:
Skull Kingdom, WonderWorks, Ripley, etc...there's also a flight simulator where you float in an air tunnel- never been, sounds too scary to me. And don't forget the water parks-WaterMania, Wet and Wild, and the multiple at Disney. (Although it might be getting chilly for water parks/beaches)
For nature buffs, go on an airboat ride. There are calm riverboat cruises in neighboring Seminole County. Don't forget the Kennedy Space Center (45 min away) and you could also jaunt to Tampa. Orlando, home of tourists.