Check Natural Bridge Campground near Staunton, VA. Sheanondoah Valley area is beautiful. There are several RV parks in that area open till November I believe. There is also a Thousand Trails resort park in the area that we heard was nice.
Hope That helps some

In mid-October 2009 we had ice on the highway during the day on I-68 in West Virginia and 20s at night in Front Royal, VA, so be careful. A week later it was much warmer. I don't remember any campgrounds we stayed at that we would want to spend a month at, but we are one to two week people.