The educational websites of the Univ. Virginia and Univ. North Carolina, xroads.virginia.edu and docsouth.unc.edu cover much about the South: Music (e. g. Fenner, Cabin and Plantation Songs, hymnals of the Civil War period) to current history.

The term 'white trash' in its current significance is discussed succinctly in "White Trash: The Construction of an American Scapegoat," at http://xroads.virginia.edu/~MA97/price/open.htm.
White Trash
Even that article on working class whites is almost out of date. Are the white employees at Walmart the new white trash? Really not applicable, is it?

This term has gone through several stages of meaning since it first appeared in the early 19th c. One of its first uses, if not the first, was by household and craftsmen slaves in the South, to refer to the lowest stratum of whites (drunks, casually employed, etc.), and by black household slaves to refer to white servants (OED, quotes from the 1830s).

By the time of the publication and run-away popularity of the cookbook "White Trash Cooking," by E. M. Mickler, 1985, the term was being applied to bikers and the like and was losing its target and singular meaning.
(Now that it is used in England, it is lost to America).

Migrant white labor has been replaced with immigrant labor or machinery, the mill workers have been fired and moved north or west when Asian mills took over and the mills closed, with compulsory education the kids now are selling cars or real estate and at worst are working at Walmart. That free-form family down the bayou that rents leaky boats to fishermen might be shiftless to some and white trash to a few but most recognize them as 'free souls.'

Where are the people of Steinbeck and Guthrie? Gone, targets no longer.
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RED EYE GRAVY
After cooking the breakfast meat (bacon, ham or sausage), remove it from the iron skillet and put it aside. To the drippins, pour 1/3 cup of strong coffee and stir while on the fire. Pour over hot grits or sop up with hot biscuits.
White Trash Cooking, p. 48.
(Available at amazon.com, in its umpteenth edition, but now accompanied by No. 2, More, and a Treasury, of White Trash Cooking. The soul food of Southern whites)