The Virginia State Library has the deeds of Fauquier Co. and other Va. counties) on microfilm.I get them at my local library from Richmond, but I live in Virginia and do not know if they are available through interlibrary loan.
I also have on my bookshelf Fauquier County Virginia Deeds 1759-1778, Compiled by John K. Gott.This covers deed books 1-6.The book was published by Heritage Books of Bowie, MD in 1988b (www.heritagebooks.com).The abstracts are indexed, so you can find witnesses and owners of adjacent lands.(I find no Wilkenson listings.)
Those interested in Moses Allan will be interested in a brnd new book--They Behaved Like Soldierns: Captain John Chilton and the Third Virginia Regiment 1775-1779 by Michael Cecere (also Heritage Books).This book draws on the letters and diary of Captain John Chilton, under whom Moses Allan served.(I have no affiliation with Heritage books or sell books.This is not advertizing, but making sources known toresearchers on the Allen and other Fauquier families in response to a query about my sources.)