Here's another article that takes the story back to the Kansas-Nebraska Act of 1854, when the "states rights" controversy that split the Democratic Party in 1860 originated. This is about Major Jeferson Buford of Barbour County AL, who organized an colonial expedition to Kansas. The open question concerns whether these people seriously intended to establish themselves in Kansas, or went simply to influence the state constitution's recognition of slavery. The same may be said of colonial expeditions from New England who came packing "Beecher's Bibles."
The Buford expedition came to my attention quite by accident as I studied demographics of Barbour County in 1860. It seemed odd that a number of families had small children born 1855-58 in Kansas. Some families even named daughters "Kansas". I don't know how many went to Kansas to stay, but by 1860 many had returned to Alabama. Some might have stayed west of the Mississippi and removed to Arkansas, Louisiana or Texas. Jefferson Buford returned to Barbour County where he died in 1861.
Imagine the impact of citizens in Alabama who heard from a man who had been to Kansas and exchanged shots with hostile abolitionists. It wouldn't take long for many more people to have heard second-hand stories based on his account. Imagine then the impact of the John Brown attack on Harpers Ferry in October 1859. The "states rights" controversy that split the Democratic Party in 1860 might be seen today as a hypothetical issue, but it was very real to Southerners of that day.
For Kansas testimony, here's an example of from letter written by A. J. Hoole, June 8, 1856 --
These are still exciting times here. You may form some idea of them when I tell you that I never lie down without taking the precaution to fasten my door, and fix it in such a way that if it is forced open, it can be opened only wide enough for one person to come in at a time. I have my rifle, revolver, and old home-stocked pistol where I can lay my hand on them in an instant, besides a hatchet & axe. I take this precaution to guard against the midnight attacks of the Abolitionists, who never make an attack in open daylight, and no Proslavery man knows when he is safe here in this Ter. Some of them go so far as to guard out every night. There are three families of us here in a hundred yards of each other, with seven men in the three families, so that if no more than a dozen or fifteen comes at once, we will be able to stand our hand pretty well. From past experience, they can't stand with even two to one. In an attack which they made on the little town of Franklin, about 12 miles from here, one night last week, six Proslavery men guarded cannon against a company of the rascals, variously estimated at from 50 to 1,500. Five out of the six were wounded; one of them dangerously, the ball passing through his body.
Rev. Hoole of Darlington SC brought no slaves with him and worked as a carpenter to support himself in Kansas. However, he writes home to a slave-owning family.