If you have the time, not much more than you might think is needed, jump over to US17 south of DC. Better roads and much, MUCH less traffic. Made the drive home from Charleston SC. Was a very nice drive even at the height of the summer vacation season.
Miles per day is going to depend on you limits. Open, smooth roads with minimal traffic I can go from dawn to dusk. Make a run along I95 anywhere north of Richmond and I'm ready for a CG after a few hours. For the West Coast forum members doing an I95 run anywhere north of DC is about like trying to get from San Diego to Oxnard on a Friday.
Even though the tire installer ment well get the coach weight checked and reset the cold tire pressure according to your load. Good time to do it with a big trip on the horizon. Your probably loaded up with more stuff than you need and as such at a good weight to keep the tires pressure at even if your next trip is just a weekend at the beach.