1999 Honda Odyssey shake,rattle,

My husband’s Odyssey has 127,000 miles and runs great; however, at about 65 mph highway, there is a vibration. And when he hits the many potholes on Massachusetts roads, there is a definite ‘clunk’ sound. Is this a strut problem? Tire? He bought the minivan used at 96,000 miles and has not had brakes, or replaced tires. We are retired so most driving around town. Any thoughts?