I’d be looking at the heat shields on the exhaust. If they are good, hit the muffler with the palm of your hand to see if you hear the rattle. Sometimes mufflers break apart internally causing a rattle like that.
As a general practice, tires should be replaced about every 5 years. In my view, tires are the most important part of your vehicle.
More info on finding noises here: http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car
Good hunting and keep us posted on what you find.