A friend in MN bought a car in Denver - he wired me the money, I brought cash and bought the car for him. If you know someone local, that's an easy way to do it.
I recently bought a 500e that I found on cargurus.com They have a service where you can pay though them (they act as escrow). So one crazy idea would be to have the seller and you both join the website (free, i think), list the car, and buy it through their website.
I bought a car in Texas once, and I picked a local shop and called them to set up an inspection. Once the car was there, I felt pretty sure that I could track down the seller if he finked on me, so I simply mailed him a check and he mailed me the title. Easy peasy.
For my Lancia, the seller drove the car 2 hours to a friend's house in PA, who paid him cash. She then kept my Lancia for me until I could fetch it. Poor girl, having to drive a Lancia for a year.