Folks, I'm an Aussie and have long dreamed of an American road trip. In May 2016 I will be in Austin for a training program and then in Washington for a conference early June. So I thought this would be a good opportunity for a road trip. I'll have a little under 2 weeks to complete the trip from Austin to DC. My wife and I are very interested in interesting natural sites (parks, lakes, wildlife etc), as well as history and less interested in too much time in cities. We don't want to camp out (we're seniors with a bit of arthritis) and prefer to stay overnights in motels or hotels.
Any suggested routes from those with local knowledge would be much appreciated to start or thinking and planning.