I'm glad they are having the reenactment this year! I was there for the 150th (2014). It was a beautiful time of year and the fall foliage was outstanding. Do be prepared for possible below freezing nights if you're camping--take warm bedding and outer clothing! I was in a thick wool shawl, a wool sontag, and with modern merino wool base layers (aka long underwear) hidden underneath my 19th century outfit,, and I still froze! At night was OK because of the camp fire, but there was a cold wind the last day that cut through my clothing.
I'd loved to have taken an extra day or two to drive along the Blue Ridge in Shenandoah NP at the fall foliage peak, but my son was providing the transportation and he had to get back to work. Also, pulling a horse in a trailer is not exactly suitable for scenic drives. But if you have extra time, consider this option!