It might be worth it to see if you can get an eco-rental to drive the route with. Compare different ones if you can.
I recently saw an Enterprise facility in Buffalo that had a fleet of Prius. It was really cool to see all these hybrids being driven out of their lot by renters. You could call to see if they have anything similar in your area, or try something like:

http://www.evrental.com/

If you're not part of the solution, you're part of the precipitate.