The Pro Shop is just a mile or so south of Dillsburg, PA on Highway 15 on the right. The field is a couple more miles farther south on the left side of the road.
The emplyees there are really flexible and willing to indulge you when you're setting up games. They are also the only field in PA to allow you to use non-field paint. In fact, their paint prices are so good that you really wouldn't want to buy your paint anywhere else. They have several well-maintained netted-in speedball courses. There is an abandoned village course that works for both large and small groups, as well as a huge castle (which I have never played on with a large group).