Sorry for delay in responding. In fact, you may be in Gettysburg already. I have a child attending Gettysburg College so wer're out there several times a year. We usually stay at:

Gettysburg Hotel - great location, right on the square. Rates are reasonable. It's actually owned by the College. While it's not a world class hotel, it's "good enough" for Gettysburg.

Wyndham - a few miles down route 30 near intersection with rt 15. 5-10 minutes to downtown Gettysburg. Property is fairly new-ish and rooms are nicer, IMO, than the Gettysburg Hotel.