Good luck then cause your gonna get a big range of $$$. I am assuming your afraid your leaving money on the table, otherwise just give him a price and live with the decision. Book value is of no real use in a truck like this.
It doesn't really matter what folks on here think its worth. Its worth what someone is will to pay and what scratches that persons itch. Besides, the purchase price will be a fraction of the money that will be spent on this.
You will get prices from 1500 to 10k or more out of this group...