Last car I bought out of state, I had the car PPI'd by a independent shop. Then the agreement was, the shop that did the PPI would hold the car until the funds were sent to the seller.
Once seller confirmed receipt of funds, he gave permission to the shop to release the car to me.
I also had a copy of title, where seller lived etc and had numerous calls and emails with him
Find a independent shop here
.
http://www.pcarshops.com/
Cheers
Derek