Even if you want to do a weekend separate from the Getaway, Ramblewood might be a good facility, providing the weather isn't too cold. (For a cold-weather place, may I suggest a seaside hotel in off-season, where the rates will be cheap? Places on the [New] Jersey shore, or Ocean City, MD come to mind.) And as Dean noted above, there are logistics to be dealt with; insurance, and cash to guarantee the rental (and cover shortfalls, if attendance isn't what it's supposed to be).--Charlie Baum
Note to Erik the Viking: US Civil War sites such as Gettysburg, Antietam, and Harper's Ferry are within an hour-and-a-half's drive of the area.