We take a different route. We leave early in the morning depending on weather or our mood we take Garden State Pky to the Cape May Ferry or TNPK to Delaware. Then head down the Delmarva. Rte 13/south/rte1..then 13 south over the Chesapeake Bridge Bay Tunnel (restaurant in the middle good place for a break) TO 64 East ( YES 64 East) to 17 south all the way to Myrtle Beach. It's not quickest, however no heavy traffic or 16 wheelers. The heaviest traffic is in the Virginia Beach area which is a little tricky.
Going down we stay overnight in Williamston, NC at an Econolodge nothing fancy but clean and indoor entry to rooms. Continental breakfast served. We are down in Myrtle beach by noon the next day. We usually drive straight through going home takes about 12 hrs.
Will be on our way down in a few weeks.
