I always demanded full purchase price in cash before test-riding one of my bikes. What's to stop him from riding to the end of the block and laying it down, or running it into a parked car? You lay it down, you may as well just pick it up and ride it home. Here's your title. Thanks for the cash.
If I were to sell a car, I'd just do a ride-along once I verified a license and insurance.
Just hang on if you can...there's a lot of freaks on Craigslist, but then you'll eventually stumble across your perfect buyer.
My favorite questions are "will you take x for trade?", "will you take payments?" and "will you deliver?".
A resounding "NO" on the first two. I'll deliver a piece of furniture or a car within a 10 mile radius.