Driving from Charlotte, NC to DC
Fishmonger's, Durham NC... a little bit off I-85 but worth the detour. Don't be put off by the ambiance (or lack thereof) - strap on a bib and get to it.
Other possbility is Allen & Son traditional eastern Carolina BBQ, on Highway 86 off I-40 exit 266... again maybe a few miles out of the way, but worth it. Have a slice of sweet potato pie.
Blue Ribbon Diner off 85/40 in Mebane. It'll be less than 2 hours into your trip, but it'll make a good lunch stop. I recommend the Applejack Grilled Chicken Salad, Chicken Pie (Sundays and Mondays only) or any of the other Applejack Chicken items.
Blue Ribbon Diner
1004 Mebane Oaks Rd, Mebane, NC