I just got back from a trip to the coalfields fo McDowell county, WV (two counties down from Boone).
A lot of hard-working folks of limited means, struggling to keep body and soul together in a crappy environment. I saw a lot of run-down houses, towns that have seen better days, and mountains with the tops ripped off.
One surprise was the number of African-Americans I saw. It is not just "white trash" in those hills. (I can't vouch for how trashy these black folk were, they looked like working people, but the folks in McDowell are not just white.) My father told me the coal companies brought them in from the Deep South to bust the UMW (or at least give the coal companies another source of labor.)
That said, the White family in Boone County are over the top and were selected precisely for their character (or lack thereof).