Check out a 2005-2009 Lacrosse.I absolutely love mine. Mine is very smooth riding, very quiet and gets great (30-33 hwy) mpg as well. For your price range, you could get a very nice one with very few miles. Also, a Buick Lucerne would be a good choice, the Lucerne is bigger and nicer than the Lacrosse, but either is nice. Buicks in general are very smooth riding cars that can really eat up the miles at 80 mph. And they are reliable as well.