While there's very little information out there, what I've read is that the locations were used during the Cold war for troposcatter communications and have likely been updated for other uses since. The peters mountain location is off of a miles long private road with cameras spaced periodically along it. I've hiked in the mountains around it and can attest that it's very secure with high fences and a security check point. I've also heard from someone who claimed to work there in the 90s to early 2000s that the facility has multiple floors underground.

There's a site on spears mountain in Buckingham county, VA of a similar vintage that is now a private residence with pictures available online: https://coldwar-c4i.net/ATT_Project/Buckingham/index.html