I was surprised the first time I saw the BCV self park how close it is to the villa building itself. Also, its not huge and we generally always find a spot close to the building.
Our trip this past Jan, we used the self park almost always, and I drove to & from AKL, GF, Downtown Disney & off site. No problems. Everything is very well marked. To get to the GF, you have to actually enter the MK parking gate. Its pretty close, I think what the other posters are referring to is the parking in general at MK and how that is a hassle.
But on the whole we love having a car with us at BCV.