Well,
All did not go as planned. I arrived to find the truck was not in the lot. Mom was on her way but described the location it WAS in. Long story short; it had been towed. Fairfax, however, could not find a record of authorizing the tow, so it's now an open question who towed it and to where. It was in the lot of the Audrey Moore Rec Center, and the manager on duty there said he saw the tow truck but figured the county had towed it. He also said there were several people asking about who owned the truck and at least one who asked how long it had to remain 'abandoned' on the county property before he could file for an abandoned vehicle title. Vultures, vultures, everywhere...
I'll report back any results when I have them.
Thanks anyway to all who offered.
-Jim