You've done the necessary and now you must roll the dice or stand pat. No one can anticipate when that A/C, belt tentioner, transmission or other pay check eater will occur.
Its been checked out, I presume the price is OK what are you waiting for; if you want a guarantee those cars are running over $50k.
The question faced by so many; whether to drive a real car with risk or drive a POS with a warrantee. Go for it! Whats life without risk, such a car for so little money.
(BTW I checked the NADA older cars guide and they show $17k as average retail which no private seller ever gets - so he is right at the top of price - which is fine for a well maintained car)