I might get into trouble for saying this, but where Berryville isn't just a bedroom community for wealthy city folk transplants, it feels (to me) like an economically depressed rural area. I think that is what would help explain lower test scores (the D.C. commuters who might be higher income don't often have kids to elevate scores). OTOH, maybe in Berryville resides many middle to upper middle class retirees who sought out exactly what you're looking for, and I just didn't see them in my stays within that area.
If you're looking for a small town with a real country atmosphere and a close community, you might have to exclude anything with a 1.5 drive from Northern Virginia.
Other options to consider might be:
Rocky Mount (pop. 4,500 or so, county seat of Franklin County, about 30 minutes south of Roanoke):
New Page 2
Abingdon:
The Town of Abingdon, Virginia
For the most "country" w/ the least population you might tour the Monterey, VA area:
Highland County Chamber of Commerce, Monterey VA
I'm sure others can chime in.
Sean