The road was THE way to get from Sedalia to Lexington at the time. It was the major stage and mail line built about 1850. If memory serves there was a skirmish at Dunksberg (originally named Bee Branch for the creek then later changed to Sigel in honor of the general) in 1861 involved a Captain Wallace and McGuire. The location of Dunksberg now is listed east of the county line but the historic site placed it just about on the county line of Johnson and Pettis county.
From Johnson county history: Stage Coaches. — One of the principal highways that became what
was known as stage routes in the early days when the mail was carried
by that means was the Georgetown-Lexington road. A mail route
was established on this road in 1857. It ran through the northeastern
corner of the county and served Bee Branch postoffice or what was later
known as Dunksburg. The Jefferson City-Independence road was an-
other recognized stage line. Stage lines also ran from Warrensburg to
Lexington and from Warrensburg to Clinton. The regular schedule
trips of the stage coach over these lines varied from daily to weekly.
As the country through which these lines passed became more thickly
settled the frequency of the regular mail delivery was increased.
Johnson county depended altogether upon the stage coach for its
mail delivery prior to the Civil War. .'Knd. even after the Pacific
Railroad was built in 1865. many parts of the county continued to re-
This google books link has a more precise location for Cook(e)'s Store on the stage line:
https://books.google.com/books?id=g6NjrZIHzl0C&pg=PA130&lpg=PA130&dq=lexington-georgetown+missouri+stagecoach+line&source=bl&ots=ZaZbefA3Id&sig=9QeeQAM7CAjlaDSgfAuNhIfGvVU&hl=en&sa=X&ved=0CCkQ6AEwAmoVChMIhe3F8L-byQIVAZQeCh1fNAKL#v=onepage&q=lexington-georgetown%20missouri%20stagecoach%20line&f=false
The Union Pacific railroad line was roughly following the road and was of course in a state of unfinished construction in the area during the war. So it doesn't take much thought to say the were following the road north with attention to the railroad bed route clearing as well.
Hope this helps.
John R.