The same could be said for the barges that ply the river in both directions, emitting a low, diesel roar and loaded with grain, gravel, giant rocks, oil and other commodities. Visions of these football-field-sized beasts swamping and slap-chopping our tiny boats had cost me sleep in the weeks leading up to our trip, and I certainly would not advise playing chicken with one in a fog, or traveling around a bend in mid-channel. But without diminishing the importance of vigilance and common nautical sense, there is nothing in their wakes to alarm a moderately experienced sea kayaker.

The most common sound is the surprisingly loud complaining of the river when it drops over and around the various contrivances of the engineers. It seemed to us that an Army Corps reading of 17 to 19 feet at St. Louis was actually better for paddlers than 15 feet, because the higher water covers the miscellaneous rock works, giving the visual impression of a free river. What’s more, once a paddler is comfortable with the current, the quickening drop, followed by the clot of whirlpools and eddies, creates interludes of adrenaline, which is to say fun.

The higher water also assured us that the chutes and sloughs that pass behind and around the various islands would have adequate water for passage, and it was along those narrower passages  though they were often big enough to be important rivers in any other part of the country  that we occasionally spotted deer, beaver, small water snakes, large herons and birds of prey. We looked for, but never saw, the coyotes we heard howling at night, sometimes closer to our campsites than we might have liked.

One afternoon we surprised a local family out catfishing; they were the only other recreationists we saw on the entire voyage. “Hey, come on over,” they called out from their campsite, a cluster of wall tents hidden almost entirely in the woods. “We got fresh fish frying and cold beer.” A very good combo indeed.

We might have seen more wildlife had we gotten up with the dawn and paddled till dusk, but we chose instead to read into the nights by the lights of our headlamps and sleep late; whether this was the influence of my teenage companion or the lull of the river I can’t say. We also might have covered more miles, but we stuck to our plan of no plan and dawdled with abandon.

On the Missouri side of the river we stopped once to check whether a dark spot in the bluff was the opening to a cave  it was not. We stopped another time to take a close look at a long row of boxcars on a siding. I will neither confirm nor deny that we climbed a ladder and ran along the top of the cars, high over the Mississippi, jumping from car to car, pretending to be Ernest Borgnine and Keith Carradine in “Emperor of the North Pole.”

On the Illinois side, we stashed our kayaks partway up One Mile Race Creek and walked along the levee about a mile to Fort de Chartres. Constructed in the 1750s and now fully restored, the fort was the military and administrative center for what was the breadbasket of French Colonial activity in North America. A few weeks before we arrived, the fort had been stuffed to the turrets with “living historians” dressed up as fur traders, native trappers and French infantry come for the annual jamboree, but when we got there it was deserted, except for the friendly woman in the gift shop who sold us ice-cold Sprites and told us about her technique in the tomahawk-throwing competitions.