I wouldn't try and talk you out of using the AAA pass if you can but are you aware of how far away the AAA lots are from the parks?
You might be better off if you do regular parking and take the trams. They bring you closer to the parks than if you park in the AAA lots.
I always bring a handicapped person with me to WDW so I park in the Handicapped area. If he didn't have an electric
scooter I don't think he would make it from the parking area to the parks.
WDW handicapped parking is on the right of the tunnel to TTC. You have to walk down the tunnel and up again then into the TTC, then to the monorail. Quite a hike for elderly people. You might be able to find a wheelchair to use until you get to the TTC, but they are not always there. The AAA lot is farther away than the handicapped area.
In Epcot the AAA lot is on the right about 5 lanes away from the handicapped. A hike but not as bad as WDW.
MGM AAA lots are in the 2nd parking area, where the busses turn. Another long walk.
AK area is down past the handicapped area. I find this the hardest of the walks, not because it is farthest but because there is no shade at all and you are in direct sun. It is farther than the MGM and Epcot walks.
I would try for a handicapped pass if you can if your parents are walkers, but if they are not the trams would be better for elderly. Again, the trams will drop you off closer to the parks than if you walked from the AAA lots.
Hope this info helps. Peggie