Danielsville Post Office is listed for the whole 1860 census of Dickson County. Enumerated by the Assistant Marshal M.F. Shelton,Danielsville P.O. So it would be difficult to determine from the 1860 census; if this was the the closest post office to the household of William Harris.
As there were 6 other post offices in Dickson County in 1860.
Try searching the U.S. Tax Assessment list for Tennessee. It's found on Ancestry.com. The database dates the list for "1862" Tennessee. But most of the taxes were paid in 1866. I think it would be difficult for a
Federal tax man to try to get the citizens of Dickson Co. to pay taxes in