Aside from Tim, people in the KC area aren't really aware of the NCR. They know that the tribes of the west banded together to form a great army, but that army clashed with yet another great power west of them, and so it has not clashed with the folks of KC. But aside from the fact that "there are great powers out west", contact with those powers is limited and unofficial. The Missouri doesn't flow that way, nor do its tributaries, so the trading houses of KC have little interest in the area.
KC is technically ruled by a council, elected from various trading houses and mercenary guilds that control most of the city's trade. Its de facto ruler is, however, the owner of the KC Company, a figure known only as "The Executive". The KC Company is the largest trade house in KC, responsible for rebuilding most of its ports and bridges and controlling almost half of all trade that passes through KC. The KC Company has outposts all along the Missouri; their patrols keep the river clear (and about two miles of riverbank on either side) of squatters, raiders, thieves, and rivals (that don't pay dues to the KC Company) from the wilds of Montana all the way to Jefferson (where the River Barons of the Mississippi pick up the task.) Its river patrols, along with the mercenary companies under its permanent employ, make up the bulk of KC's military might. In KC, The Executive gets a share of everything. Most settlements along the Missouri River are in reality subsidiaries of the KC Company.
Farmers of the Missouri River Valley come in many types. Tribal farmers trade with the river houses for goods they cannot produce themselves; independent farmers and farming co-operatives stake out land and trade their excess with the residents of the outposts and cities along the river for much the same reasons. A few official farming companies exist (at least one, in Iowa, directly owned by KC Company) whose business is producing and selling food for profit to the many settlements throughout the river valley - these tend to be better supplied than other farms, but also tend to produce much less variety of crops. In addition, the Missouri River Valley has a large number of homesteaders (most outside the two-mile band of the river, but some paying dues to remain within the protection of the trade houses) who simply wish some land to call their own. When these homesteaders trade, it's rarely on the river. ("On the river", incidentally, has come to hold the same meaning as "above the board" once did. Illicit trade is "off the river" or "in the brush".)