I think you are very close to being correct Kirby. Many of the "Hilderbrand allies" can trace their roots to when the "Maramac" and Big River areas were first settled. We must remember that it was really only one generation removed from Samual's and many of the original settler's were very much alive and well in the 1840's and 50's. Many of these first settler's shared family roots in North and South Carolina and came in waves or "groups" to the area.

As it relates to John L Roan (Rowan, Ruan, Rohan) he was born 1810 in Georgia. His first wife was Catherine Spalding (Spradling) his second being Nancy Cash, later married to William Doggett. Allen and John Jr are sons of Catherine Spalding and I suspect that is where the Hilterbrant (note spelling difference) connection lies in Jefferson County. There may be a Padgett/Fry hook in there as well I've got to check a couple relationships that don't seem to fit time wise in that line. I've a couple of sources to follow up out of Houck's history to see if I can make the tie in likely through Bartholemew Hilterbrant (Hilderbrand).

Names such as Padgett/Fry, Hilterbrant, Armon, House, Adams, Doggett belong in both the John Roan and Sam Hilderbrand lines and represent the earliest settler's to the Big River area all coming across the river before the Louisiana Purchase and carving a settlement area out of the woods and Osage Indians in the 1790's. Alot of their land dealings are in Spainish and French and are held at Cape Girardeau and Ste. Gen. The Seminary in Perryville has an extensive holding on the Catholic church and french settlement issues for the area as well.

FWIW
John R