My guess would be that this was not the first time...and I would look at previous vehicle rentals (via his credit card). Take samples from the back...and I bet most of the vehicles were all vans (this would be a tremendous tip for some Arkansas state trooper). You could well tie several children abductions to this idiot by the time you finished with his credit cards.
Like I explained in the Smokey Backroom. This guy was fired from his previous job as a Used Car Salesman (opportunity to borrow cars from the lot?). AND he was fired for using company computers to look at porn.
You could just about write a script for how he might have gone to Utah, abducted Elizabeth in a car not his own, deposit her body in a mini storage, and return the car back to the lot to be sold. Keep in mind, that he made a trip to Arkansas in November to RENT a mini storage unit and on this trip used a car he rented from Enterprise to carry out the crime. Planned well in advance...the monster.
JMHO...sw