Am I Being Unreasonable? Original Owner Wants Car Back

Suggestion:
The buyer is in Missouri, and you're in Utah, right?

Tell the wannabe buyer that you'll work with him, but he's gotta come look at the car before the haggling starts. See if he's willing to outlay the cash to make that trip.

That's when you'll know if this is all mental masturbation and you have better things to do, or if he's serious.