Fly over zones aren't a big deal at Camp David. Our house was about a mile from there and although we used to see the occasional Osprey or Chopper in and out there's not usually much to even know they are there. When we go back to visit friends and family we usually stay at KOA in Harpers Ferry or Ramblin pines. Harpers Ferry is right at 340/15/RT 9 so fairly decent location for access to Frederick and surrounding points. Ramblin Pines is better if you want to be East of Frederick, but sounds like a moot point if they're booked. Yogi in Williamsport is close to the 81/70 interchange but ungodly expensive (over $100/night) so we don't really stay there anymore. And it gets busy the entire season. Frankly I don't get it, but whatever.
If it were me, being the venue is in Thurmont, I'd stay in Gettysburg. Closer and straight shot down 15 to get there. Is the wedding at the winery on 15 just south of Thurmont?
