Here's a thought - no matter how you get there, when you hit the latitude of Wilmington, DE look for the signs for Route 13/113 south. Go straight down the Delmarva Peninsula, and hit the CBBT at Cape Charles. About 50 million RVs a day go over it. With propane OFF.
13/113 is divided much of the way down, and when it's not, you're cruising through highly dense and populated burgs like Pokomoke City, Temperanceville, and Onley.
113 is recommended, as it bypasses the Salisbury, MD metropolis, and there's only one traffic light between Dover, DE and Virginia Beach. Maybe two.