Just to clarify - the AAA parking pass does not give you free parking. You still have to pay the same rate (so, if you are at a WDW resort, you have free parking. If you are staying offsite, you have to pay).
The AAA parking pass does allow you to park closer to the entrance, usually just beyond the handicapped parking lots. There is no tram service from either the handicapped parking or the AAA parking and the farthest ends of some of the handicapped parking areas are quite a hike to the park entrance.
So, you do park closer, but will have a longer walk than if you parked in the regular lots and walked to the end of your row to use the tram. You just avoid using the trams.