On the National Road, in 1846, a mail coach carried President Polk's Mexican War declaration from Cumberland MD to Wheeling VA ( now WV) in 12 hours, a distance of 131 miles, or 217 km: considered a feat at the time. More normally, The Reliance Line coaches left Wheeling and reached Baltimore in 2 1/2 days, a distance of around 500 km. Both of those trips involved getting over, around and through the Allegheny / Appalachian mountains, the National Road following the route of the present Rt. 40.

But those travel times were not always reliable. Coach travel at the time was notoriously dependent on conditions. Roads- even the National Road- suffered from neglect and poor-quality repairs, so tree-falls, washouts, mud, potholes and very rough surface could slow or halt the coach . Ice, snow, torrential rain and summer heat could delay, halt or complicate any trip as well. Although you can say that the above times were possible, they were much less certain than car travel today.

Philip Jordan : The National Road