It is an interesting park even if you have no interest in the civil war, this link
Gettysburg National Military Park
shows a small fraction of the museum, which took us 2 hours to go through with reading (and I am no history buff)
, With Harpers Ferry, where you can cross the Potomic, Antietam and Fort McHenry all so close there a lot to see (and there's even more
)nearby.