We went last year. In my opinion your best bet is to get a hotel on International Drive. It's about 20 to 30 dollars taxi ride from the airport. Most of the hotels run shuttles to and from all the attractions, and they go straight through the entrances, no queuing like individuals have to do in peak season.
There is a bus service that runs all day along International Drive for a minimal fee which will get you to the Shopping Malls, Restaurant areas and local water parks, fairground areas and the like.
Most evenings we walked for miles along ID with no problems, plenty of pavements and it buzzes of an evening. Just pick up plenty of street maps and the bus routes.