I've based a couple of vacations in the Frederick MD, Harper's Ferry WVA, and Gettysburg PA area. Wonderful place for the history geeks like me
Tell him to visit the Holy Cross Abbey in Berryville. Go to the gift shop, and if Brother Thomas is there, ask him about the civil war battle fought on the Abbey grounds. The Brothers there do enjoy company, and while they don't give tours of the Abbey grounds any more, they will gladly chat the afternoon away with you. Also, don't leave without buying a fruitcake! They're literally divinely delicious.