I am descended from the Plaughers of Pendleton Co., WV, also...William and Virinda Plaugher are my ggrandparents. I'm wondering whether instead of "Rockbridge Co.," you aren't referring to "Rockingham Co., VA" I lived there several years. Rockbridge Co. is further south in VA. Mt. Clifton, Mt. Jackson, Ft. Valley are in Shenandoah Co., adjacent to Rockingham Co. Also, Pendleton Co., WV, is adjacent to the west of Rockingham Co. Anyway, I've been in touch with Milton Plaugher from Florida. He put me in touch with a woman in Broadway, VA (Rockingham Co.) who sent me many pages of Plaugher genealogy.
We're moving to Florida from Virginia and all my research material is there now. If you don't get some answers by the first of July, I'll try to get back here and give you Milton's contact.