2008 Highlander Sport with tow package

I'm looking at buy 2008 Highlander Sport. The vehicle interior 10/10 Exterior 9/10 Drivers beautifuly. It does howeverit has that rattle on cold start up and it quickyl goes away. Valve cover gaskets just replaced slotted rotors and ceramic brakes just did oil change, transmission service. New radiator new spark plugs. All top electrical connectors replaced. New water pump and new tires. A/Cblows very cold and heater works well. This is the V6 it has timing Chain. What should I be nervous about before I decide to buy. 178,000 miles. Asking $5,000.00

Thank you Tami