[gearhead]

It depends...
1) How many Cracker Barrels the DW sees and how much tea she drinks at the Cracker Barrel.
2) How bad her feet have swollen.

I have pulled the 5th straight through from Bristol Tennessee to home, about 1,000 miles. It was brutal but I knew I would be home at the other end. I'm thinking it was about 16 hours, including a massive traffic jam at Baton Rouge.
Normally about 300 miles or 6 hours on the road is a good day.
The cabover...I just did 500 miles at 8 hours per Google map, which is really 9 hours including gas and fast food lunch. A lot easier and less stressful.