WV 78 appears 1925 Official

WV 78 becomes part of WV 51 (shown erroneously to cross the mountains) 1932 Official

WV 78 #2: Appeared about 1957 as a renumbering of WV 79 from Van to WV 3 Whitesville.
Between 1965-70, WV 78 was downgraded to CR 26 from Van to Bandytown; CR 26/1 then east about 4 miles is no longer a road; CR 3/15 through Blue Pennant to Whitesville. The segment from Bandytown towards Whitesville was shown as a primitive road on the 1949 Boone County map.

WV 79 from Van to Whitesville 1956 Shell

WV 78 from Van to Whitesville 1960 Power Facilities

No route at all from Van to Whitesville 1973 Official

WV 78 #3: WV 78 was assigned to the proposed Shawnee Parkway in a late 1990s WVDOT number assignment document (no longer available online) as reported by HB Elkins.
The Shawnee Parkway would run from I-77 Ghent southwest to Ashland where the King Coal Highway wold be built as a relocated US 52
At some point the designation was changed for some reason to WV 154. Only CR 48 right near I-77 has been improved and it is still CR 48.