Hi Lizzie84 - Lizzie64 here.
We just got back. I have never stayed at any of the All Stars, but have always rented a car and driven to all the parks, with the exception of 4 nights this last trip when we stayed at the Poly and monorailed or boated to MK and Epcot.
Driving to any of the parks is about a 10 - 15 minute drive depending on which park and which resort. Nothing is more than 20 minutes away.
As for Disney Transportation, if you have small children, I wouldn't recommend it. You have to collapse your strollers and take all your packages out. This is why we always drove.. We found it too much of a pain to take the babies out of their strollers and all of the bags and stuff out of the strollers to board the bus. It was much easier to wheel them to the car and unpack there.
If you don't have kids, then definitely give the buses a shot.