Sounds like a good price.. I just picked up an 08 Limited with 170 for 15K. Other than the mileage, the thing is awesome
I would look at Kelly Blue book. I am pretty sure you are at or around the private party price on that.
Get a carfax and search the maintenance records online. Feel under the lip of the hood near the front windshield. If it feels rough, that means it was painted. Look at the stickers and barcode on on the inside of the door frame. If they are crooked or there is a line of paint around them, the vehicle has been repainted. Look at the screws on the frame, if the paint is chipped ar marred, the fender had been taken off to possibly paint. Look for overspray under the hood.
Drop it in reverse, and hit the gas hard... do the same thing forward, then hit brakes hard... Hear a THUNK, engine mount bad.
I used to appraise trade-ins when I worked at a dealership. You would be surprised how often people said nothing was wrong with their cars, until you show them how messed up it really is. They knew, just tried to get one over.
Some private party sellers may do the same. Take it to a mechanic to have the vehicle checked. Hopefully, the owner was a 4runner lover and took good care of it.
Good luck!
Squ1d