At that point, I turn off and get a steak and some beers and spend the night in a motel. Usually around Winchester, VA the first day and Savannah, GA the next day.
Works for you.
When I drive, 600 miles is okay but I’ll drive and drive, sometimes more miles, sometimes less, just listen to satellite radio and relax. If I feel like stopping, I stop. If not, I just keep going. No chore for me, I just want to get where I’m going.