Harpers Ferry National Historical Park
Just up the river is Harper's Ferry National Historical Park. It is another historic ferry crossing, only this site developed into a major center of commerce and a focal point before the Civil War and then during the war. You'll find plenty to do at Harper's Ferry for more than a day.
You can drive the backroads between Shepherdstown and Harpers Ferry, but expect to feel disoriented and for it to take twice as long. It's a great way to see rural life in this part of the country, but your best route is to take the Charlestown Road out of the southeast side of Shepherdstown (down by the Yellow Brick Bank Restaurant) until you come to a junction with a sign to Harpers Ferry. Take the left fork. If you miss the turn, head on into Charlestown, where you'll pick up US 340, east (left) to Harpers Ferry. The turn off, joins US 340, just east of Charlestown and avoids town traffic.