When you are traveling with a child that age you want the resort with the easiest transportation. Having walking or boat access to two parks is a big deal. The Waldorf would have more luxury but Swan/ Dolphin location and was of getting to the parks makes a difference. The S/D also has a great assortment of restaurants and it is close to all that the Boardwalk has as well. I would still drive to Ak and maybe even MK because schlepping all that stuff like a stroller and bags, is not fun. The stroller has to be folded up before getting on the bus.
I don't think you can walk from Waldorf to DTD anyway. I don't think Chelonia Parkway or Buena Vista has sidewalks in some sections! And it is pretty far.
Edit: yeah, I just checked and it is like 3 miles, lol!