This is a Civil War map of Rockbridge Co. Va. It would be a few years after the time of John Moffett but I do find Dryden on the map which might be a guide to location. You will find Falling Sprg. Church on Buffalo Creek where Rev. Junkin, the minister is listed. The Buffalo Forge wouldn't be the one you are seeking because it was sold by a Wilson to a Weaver in the 1820-1830's. It still stands today but the info on the house doesn't fit yours. Rockbridge Co. currently does not have a Moffet's Lane and the present church is a mile from the first church. I did find the Moffets in the present cemetery. There are several mills listed but I only know of one forge which is Buffalo Forge.
You can google this on the National Register and all related names/dates are listed.
There are several Grigsby properties in that area in which the Grigsby daughters lived when they married.
PS The link is not working. Google Civil War Maps of Jedediah Hotchkiss and it should give you Library of Congress Memory site for maps. Enter Rockbridge Co. and choose the one with 186? . You will have to use the zoom in and guide to pinpoint Buffalo Creek area.