How long can you afford to sit on it and wait for the best price from a buyer? Do you have to register it in your name before you can resell it? In my state you do, they want their tax money, which is more out of your profits. That truck has some life left in it but it's an SR5 with 200k+ miles. If you got it for $3800 to $4000 I think you could do ok. Obviously you're not in love with it and you're not buying it for you which is a HUGE plus. Show up with $3800 cash and wave it in the guy's face. Once he deals with the usual craigslist *******s and tire kickers, he'll be much more willing to take the no hassle cash that you had in hand.
I'm guessing he already had a dealer appraise it as a trade in because he mentioned wanting to get the wife a newer 4runner. This is probably an attempt to get an extra $1-2k out of it.
There are a couple easy things you could do to make it nicer too. Get those headlights cleaned up, maybe $20? Black out as much of the frame/tow hitch/exhaust etc as you can with a few cans of spray paint - another $20 that makes it look ten times nicer. The cladding doesn't look too bad but the pics aren't great. For $20 you can get some of the wipe new stuff or whatever and make it nice and dark again. If you're really feeling froggy - get some white plasti dip and do the side view mirrors, the unpainted ones look cheap. Also, no pics of the interior but $50 spent on detailing the interior goes a long way. For less than $150, you could have that truck looking nice for the next buyer.
