I think that's sort of up there for an '07. As everyone else is saying, my truck has been problem-free since I got it (a '03) in '06.
If you're really interested in this particular 4Runner, find out more about it. Where is it located? Is that a place that would require mostly city-like driving or is it not so stop-and-go? If it's city-like, then you need to be more concerned about things because of wear and tear. I'd rather get a truck with a little more mileage if it's been driven in a country type of area (without traffic/lights and such), then get one that has less miles but it's been driven in a city or something; they're rough miles. This would be my biggest concern when it comes to mileage. Also ask the seller what they were using the truck for (to get to work everyday using the highway, or what?)
With the 4Runner though, I don't think it would matter so much. I'm sure it does slightly but I've never had such a dependable vehicle in my life, and I drive a mix of everything.