I grew up in that area and have stayed at the Harpers Ferry KOA a few times going back to visit. Harpers Ferry itself is rich in history and there are some tours and I think even a ghost tour. A few little museums etc. Restaurants in HF itself are hit or miss. For really great food go to the Guide House just across the river. If you want more history you must visit Antietam Battlefield in Sharpsburg. About a 30 min drive. Lots to see there. I worked there as a kid in high school and there is a lot to it. They have tours as well. The tower at Bloody Lane is cool, Burnside bridge etc. There's also the Washington Monument state park in Boonsboro. (not THE Washington monument, but that's what it's called) It's a nice little hike and you can climb inside the tower there as well. There's Hiking all over as the Appalachian trail runs on the neighboring ridge from HF. There's also Cunningham falls about 40 Mins away. beautiful place. And about 20 mins North of there is Gettysburg (if you haven't had enough of history). Washington DC is about an hour and a half from HF. If you have Bikes the C&O canal is fun although locks and lock houses etc are sparse. But it's a pretty ride. There's also lots of whitewater rafting tours that are fun.
Small little towns here and there, Boonsboro, Brunswick, Middletown, Shepherdstown each with their own little shops and restaurants. There's a really nice City Park in Hagerstown, but that's about all Hagerstown has to offer Sans Wal Mart and lots of people. Frederick has a LOT to offer in the downtown area. Restaurants, shops, etc. Market street area is really well preserved. It does get busy in the Summer.
Feel free to PM me with any detailed questions. Happy to Help.
Have fun!
On edit: I just read that the Guide House grill location across the river has closed, but says they are opening a new location next to Harpers Ferry Brew company. Hopefully it's same fantastic food.
In Frederick I recommend: Lapaz or the Orchard - but really anything on Market St is great, In Middletown There's the main cup and Tapia's on Main, Shepherdstown we like the Blue Moon Cafe. In Brunswick Beans in the Belfry is a fun little joint. A friend of mine used to play Jazz there on the weekends.