1. Seems like a decent price if it's in good shape but I agree with kilroy - prices are somewhat regional so go to autotrader.com and see what similar 4Runners are priced at around you.
2. 4th Gen 4Runners have been known to get frozen calipers, especially if you live where they salt the roads in the winter. Obviously you also want to look for a decent service history. Not a bad idea to have a compression test on a car with that many miles before buying. There have been a few bad head gaskets reported so the compression test should show you if that's a problem or not. A hydrocarbon check in the coolant is also used to detect head gasket problems but there are other things than can cause bad compression so I like the compression test.
3. I am a big believer in starting with fresh fluids anytime you buy a used car. For a 4Runner that means engine oil, transfer case oil, and the front and rear differentials. With that many miles you should also evaluate the coolant and brake fluid and change if necessary. I personally would do the transmission fluid as well unless you have documentation to prove it's been done recently. Starting in 2004 they went to a sealed transmission so there's no dipstick to check the fluid. You basically drain and fill the pan a few times (running the car between) and you should cycle out most of the old fluid.
I would also change the plugs. The factory plugs are supposed to be changed at 30k so hopefully they've been changed by now but I'd put a fresh set in unless, again, unless it's documented that it's been done very recently by a decent shop or Toyota dealer. I wouldn't trust the previous owner if they did it - maybe that's just me.
