[jyl]

Your solution doesn't give you any practical protection. If he stops or bounces the check, you just have a piece of paper, not much better than the piece of paper that is the check.

I would not hand over possession of a car without a cashier's check at minimum, better yet take the cashier's check to the bank, verify funds, and deposit right there in front of the buyer.

There is no reason why he cannot do this. If he has to wait a week for the car or take a weekday off work, so be it. You have something he wants, so you are in the drivers' seat.