We attended last year.
Definately plan on taking a cab! From the resorts, you would needs to take a bus to the transportation center at Disney, and then you can take a bus to Wide World of Sports complex. Check with the resort, they can probably call for you. It takes a while to get checked in, so leave plenty of time. You need to check your gymnast in, and then wait in line to buy your ticket. Your dd will need to wait with you, since buying the ticket is outside the facility.
Not sure what level your dd is, but I heard last year they gave ALL the L4's a medal at the end.
Have fun. I'll be in FL that weekend also, but will be on west coast visiting in-laws.