Not older than 10 years old, parts are going to start failing on your watch. (I make exceptions for toyotas and jeeps)

Not over 140K miles, most common engines start having problems around this time, or require rebuilds.

No Private Sales, they ask too much for the vehicle and know it's about to cost them thousands (some part is about to go) so are just looking to get out from under it. If it was worth a damn, the dealership would have taken it as a trade in for their new one.

must have 4WD or AWD I live in the north, so I'd rather not have to deal with shitty roads in the winter.

For me personally, I also have a rule against ALL GM based products. Those are hillbilly cars and cookie cutter mobiles.