I would not choose a date on craigslist either, but don’t have any problem with cars. They could be as good or as bad as the cars on the dealer lots. You should find a car being sold by its owner, who has owned the car for at least more than a year and has the clean title in his/her possession. Like any used car purchase you should inspect/test drive the car and then have your mechanic inspect it. The title and money transfer would ideally happen in the local DMV office so you know you are not buying a stolen car.
As far as the Matrix, I am 6 ft tall myself and have been pretty comfortable in Corolla’s, but that was not the case with the Matrix. Actually I stopped my test drive just about when I was trying to back out from the parking spot. I should add that my legs are disproportionally long.