Busch Gardens is a wonderful place. When last we were in Orlando, we took a shuttle bus (possibly Mears??) from Orlando directly to Busch Gardens. You might want to check with a travel agent or goggle the request for this shuttle. The bus was airconditioned and had a dvd playing. There also was a bathroom. The nice thing was that the drive on I-4 is very congested and we didn't have to drive it after a long day at the park. We had considered renting a car for the trip but decided that we'd prefer to be driven. You might also want to check the Busch Gardens site for any information they have about this shuttle. It delivers directly to the entry of the park. The cost was reasonable compared to getting a rental car, parking, gas, etc.
Hope this helps!!
Hope this helps!!