Not really walking...dinghy trip up the fresh water river! We started at the river mouth (where lat long is) and went over the bar at near high tide. Had minimum 7 ft going over the bar, so could probably do at most tides in a dinghy carefully , except low low tide. Able to go up about 2.5 miles (as the crow flies) until we arrived at some rapids. 2 small settlements, many birds (parakeets, parrots, hornbills, fruit bats. Drifted downriver for an hour. Fun trip, best late in the day or early morning to see the birds.
If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea.