Hey Jeff
There are a ton of waters around Gettysburg that are worth fishing. Your closest choice would be the conewago. Fishing there was slow towards the end of the summer. That stream has almost no holdover. I know they re-stock it, and I'm not sure if that has happened this fall or not. I did drive past the other day and noticed the water was low and slow - I would pass on this one for now.

The safe bet would be a quick drive up to Carlisle to fish the breeches, the letort, or big springs. You could also head out to chambersburg to fish falling springs. My first choice would be the Breeches. I'm not sure if you fish spring creeks often, but they can be pretty frustrating. When I want to go out and bust my tail for a seven inch trout, I go to big springs. When I really want to be humbled, I fish the letort. The breeches always has fish rising, and the crowds haven't been that bad lately. I would be more than happy to shoot you directions. I work in Gettysburg and Live outside of DC, so I can probably give you a hand from anywhere. Just shoot me a PM.