Hello E.D. This is from Wikipedia.

"Denver at first was a mining settlement, where gold prospectors panned gold from the sands of nearby Cherry Creek and the South Platte River. Larimer, along with associates in the Denver City Land Company, laid out the roads parallel to the creek and sold parcels in the town to merchants and miners, with the intention of creating a major city that would cater to new immigrants.[6] In the early years, land parcels were often traded for grubstakes or gambled away by miners in Auraria. But the prospectors discovered that the gold deposits in these streams were discouragingly poor and quickly exhausted. When rich gold deposits were discovered in the mountains west of Denver in early 1859 it appeared that Denver City might become a ghost town as prospectors left for more lucrative claims. But once the gold rush began there was a great need for materials that couldn't be produced locally which assured Denver's future as a supply hub for the new mines.[2][7]

Before the gold rush, trading was sparse in the Denver area. Early expeditions into the area, such as the Pike and Long expeditions, had returned east referring to the plains as the "Great American Desert" which deterred immigration. Despite this, frontier posts and forts existed and traded with the natives and frontiersmen. However the closest major trading routes, the Oregon and Santa Fe Trails, didn't come with in a hundred miles of the Denver area. Until a permanent trading route was established the locals had to make due with what little extra new immigrants brought with them."

I suppose one route could have been the Oregon Trail but one would have to venture north into Wyoming to pick that up and a small party may not have fared to well. Rather my guess would be the Santa Fe Trail which loosely follows the Arkansas River near the Colorado and Kansas State line. Although Denver is known as the mile high city it is on relatively flat ground and by going southeast one could have picked up the Santa Fe Trail in present day Lamar, Colorado. Distance of about 200 miles from Denver to Lamar. The Santa Fe Trail would have taken traveler into the territory of Kansas and then on to the State of Missouri in 1859. A traveler could have gone one to St. Louis, Missouri caught a vessel south to Vicksburg, Mississippi.

From there a person could have caught a train in 1859 from Vicksburg, Mississippi to Montgomery, Alabama and it was named the Vicksburg & Montgomery Railroad at one time.

E. D. All of this is based on what money a traveler could afford but if I would have had the money I would have entertained this route.