I wouldn't worry about the mileage if it's been treated well. My 00 4Runner with the same drivetrain has 206k on it and it runs just like the day we bought it. So does my fathers 98 tacoma with 180k. Nothing but regular routine maintenance, shocks, and a couple wheel bearings have been needed. At that mileage when you do the timing belt I would also replace the idler pulleys, front crank seal, and change the tensioner. And of course the water pump. If it's an automatic you might want to consider changing the radiator to. I know 4 runners are well known for failures that cause the transmission fluid to get into the coolant once they have some miles on them. Hasn't happened to mine yet, but I'm going to swap out the radiator soon. If it's anywhere in the rust belt the frame is a concern too. But on most 01-newer trucks if it's an issue Toyota will actually swap out the entire frame, rear springs, etc. I've seen the local dealer working on a few, looks like quite a project. But supposedly 2 techs can do one in a day.