It's never a good thing to multipurpose historic sites - it signifies that the thing we sought to preserve is not worth preserving in and of itself.
McClellan's headquarters at Antietam has been given over to a branch of Frederick's National Museum of Civil War Medicine. Owned by the National Park Service, Pry House has been closed to the public for the last 30 years, so the National Museum of Civil War Medicine has at least done us the favor of inveigling the Park Service to serve the public.
A second good thing about this bad idea is that it is site-specific, not just a random collection of surgery exhibits. It focuses on the work of McClellan's chief medical officer Jonathan Letterman, a talented medical administrator whose modern biography is long overdue. Having a museum tell your story may be as good as having a book do it and some reports indicate that Pry House will present the medical aftermath of Antietam as Letterman's ushering in modern triage and evacuation methods.
Off to Pry House I will go, with a promise to report what I find.
Meanwhile, the recent study Debris of Battle reviews the (failed) medical judgements of Meade and Letterman after Gettysburg.