Dixon's Muzzle loader shop is about 90 minutes NE of G-burg, just off I-78 near the Krumsville exit. (If you go stop at Dietrich's Meats in Krumsville) Ft Chambers gun shop is about 35 minutes west along I-81 at the Scotland exit
Stop at Ft Frederick outside Williamsport Md, not far off I-70, maybe 80 minutes SW of G-burg. it is a great old stone fort built for frontier defense in the F&I war. Used also in the Rev War and Civil War. Baltimore and Ft McHenry is 70 minutes SE of G-burg. Valley Forge is about 2.5 hours drive east of G-burg.
There are a lot of little mom and pop gun shops, but in these days of the internet, it is hard to find any deals or treasures.
Winchester VA has some shops that cater to the NSSA crowd at Ft Shenadoah, Back Creek is one,
There are some great Farmer's Markets and flea markets in the area. I bought up several muzzle loaders at flea markets and yard sales last fall.
The farmers Market at Thomsville is large, same for the Green Dragon (Fridays) at Ephrata and Roots (Tuesdays) south of Mannheim.
There are literally hundreds of places within two hours with all kinds of historical ties. The Conrad Weiser Homestead, Dan'l Boone's Birthplace, the Cornwall Ore Mines, (made cannon for the rev war) The State Museum in Hbg, the National Civil war Museum in Harrisburg (sort of a joke but they have some items) The Town of Hershey with the choc factory and amusement park, Harper's Ferry national historic sight, Antietam Battle field, Washington DC, Mt Vernon, Gunston Hall,
I have lived here all my life and haven't seen much of what there is to see. Heck, I am just seven miles south of where the citizens burned the bridge over the Susq to keep the rebs out of Lancaster.