I think you mean Berryville instead of Valleyville. Yes, Berryville is a small town in Virginia on Route 7 - a few miles east of the Trail. Mount Weather is the installation on Virginia 608 between Snickers and Ashby Gap.
If you ever drive on VA 608 you can see the above ground portion of Mount Weather. It is enclosed by fencing and barb wire. As you drive by, the road actually makes a sharp 45-degree turn one way and then another - almost as if they want to force you to slow down so you can’t get up enough speed to crash through the gate (although I’d imagine this isn’t why the road is formed that way).
Mount Weather is run by FEMA (Federal Emergency Management Agency). You can do a Google-search on the web and get more details. I think National Geographic did a tv special about it a while back. Mount Weather is where the Executive Branch (President’s folks) would go during a national emergency. The Legislative Branch (Congress) has another location in nearby West Virginia at a resort (also underground). During 9/11 I believe some VIPs initially were taken to Mount Weather - not by helicopter because of the FAA initial flying ban, but by car. By the way, this is all public info - not classified.
Back in the cold war days, supposedly another Super Power (Russia?) found out that some property that neighbors Mount Weather (on VA 608) was for sale. Apparently they considered buying the property so they could monitor what happened nearby, but don’t believe the sale ever took place (or, perhaps, was discouraged by the U.S.?).
Brutus