To add to the Vernon County connection: Brown's History of Vernon county 1887 as corrected by Johnson's History of Vernon County 1911, reports:

"Mc Donald was also a merchant in June, 1850, but the first merchants were Anderson and Hays. The first resident attorneys were D. C. Hunter, Wm. H. Bluntou , and John C. Boone, all of whom were here in 1856." Pg 597 line 22..Brown's History.

http://cdm16795.contentdm.oclc.org/cdm/ref/collection/mocohist/id/93403
https://archive.org/stream/historyofvernonc01john#page/132/mode/2up/search/boone

So born Femmes Osage St. Charles County in 1816, Boone is in Boone Twsp, Green County in 1848, presumably at Ash Grove, when his 2 sons died. 1850 Census has him still in Greene County. His father Nathan passes away in 1856. He is reported as an attorney in Vernon County in 1856. 1860 finds him in St Louis area. 1861 he writes Nelson from St Louis but still has Vernon County connections. 1862-1863 in the St. Louis area working as spy and recruiter. October 1864 captured in Callaway County MO (reported in a St. Louis area paper at Concord)reported as aide de camp to Gen Cabell. Gets married a 2nd time in Benton County Arkansas 1867. Dies age 77 in 1893 at Sulphur Springs AR. He appears to be in good company with a significant number Cabell's men ending up in Benton Co Ark. post war. see http://assets.luginbuel.com/genealogy/documents//Benton%20County%20Arkansas%20Confederates.pdf

Cabell was nearly captured during the 2nd Battle of Independence Oct 22 1864 and was captured at Mine Creek Oct 25 1864. Perhaps John C Boone was working his way southeast from Independence, Little Blue area when caught in North Callaway county on Oct 24. http://www.transmississippimusings.com/pages/biographies/william-cabell.php

I'm scratching the bottom of barrel at this stage.
FWIW
John R