Hello Jillian!
Welcome to the Disney Parks Moms Panel. I have two little boys who are also huge fans of all the residents of Radiator Springs. They often ask to stay at the "Mater" hotel whenever I make plans. The "Mater" hotel being
Disney's Art of Animation Resort. It really is an amazing Resort to explore, and you can certainly do that.
In order to reach Disney's Art of Animation Resort from
Disney's All-Star Sports Resort you would need to transfer buses at a Theme Park. The closest Theme Park to your Resort would be
Disney's Animal Kingdom Theme Park. Hop on a bus headed there, and when you arrive transfer to a bus heading to Disney's Art of Animation Resort. It shouldn't be too hard and will not take too much time. On your way home do the same, hop on a bus headed to Disney's Animal Kingdom Theme Park and than transfer back to your home Resort.
I hope this has helped, Jillian! Please make sure you bring your camera along to capture those huge smiles on your son's face as he poses with those Cars Characters. It will be a memory you won't want to ever forget.
Dream as Dreamers Do,
Jen