Reddit reviews River-Horse: Across America by Boat

A few years back the author William Least Heat-Moon took a boat trip across America, starting in New York and ending in Portland. Of course he had to portage a bit to get across the Continental Divide, but apparently that was less than 75 miles, and all the rest of the trip was accomplished in the water. It's fun to follow the lines on this map and see how such a journey could work.