Whew! I just finished ALL this thread. Wasn't sure I'd make it with all twists and turns. To answer your original question, he either had inside information or was lucky as hell.
One of the twists in this is about Capt. Logan Enyart. I found it interesting in his obit after taking "the oath" he made his way to Neb. where he turned a profit after buying wagon & oxen and freighting to Denver. A yr. later he went into partnership with two others. Then got GVT. contract to move a Fort. Soon after started farming, raising stock and banking, having ranches in several states. I'm not saying a hard working man can't make good, but this guy beat the average.
One thing to remember is at the time of JJ running around, is how Tribal people were, much more than today. Clannish might be a better word. Your "Kin" looked out for you, gave you support and your cousins wife's family could be counted on for help in most cases. This allowed them to move freely through most of Western MO..