Great question, I just spent five months doing the same thing until I found what I was looking for. There are a wide variety of websites available to help you. For all, set the search mileage radius to max, to cover every listing you're trying to find.
Autotrader.com, cars.com, carsdirect.com, truecars.com are some of the biggees. Truecars does a good job of estimating a used car's value and whether or not you're getting a good deal, since used car invoices aren't ever shown to the customer. The best time to buy is in the winter since prices will be lower. Of course, who wants to drive to MN in Feb to test drive a car? If you can have a forum member check a car out for you in their locality, the option exists for the vehicle to be shipped to you. I paid $1200 to have my XLR shipped coast-to-coast. Gas and hotel expenses would have been more, plus 0 miles on the car.
CC