I would work my way to the Blue Route... OR whichever way you choose to get to 95... Run 95 to 495 around Wilmington.. Once south of Wilmington, exit onto rt 1 south... cross over the St.George Bridge and get on the new 301..
Follow 301 south/50 East across the Chesapeake Bay Bridge and 25 miles out to 95.. you will now be 17 miles above the draw bridge in DC... take it down to Ashland area or there about.. that should ne 6 hrs, or just short depending on traffic..
I just towed this route on Tuesday, my WAZE was saying to take 95 threw DE/MD/Baltimore/key bridge ect.... I hopped onto 1 south and 301, it recalculated and was 6 minutes different and was a WORLD easier ! ! ! !