This boat don't float (2009)

Usually they ended (or really, only got started, like this) up mostly drifting down, because gas costs money and diesel is the only thing available on the river, and then only at terminals that are physically and culturally intimidating to the driftboat crowd.

Most of the time, if they made it as far as BR, they were able to formulate and execute plans with a reasonable degree of linearity, as there was a lot of river upstream to weed out the reckless and feckless.

However, once they got to Baton Rouge they were in for changing conditions. The Huey Long Bridge is the farthest upstream that oceangoing vessels can navigate on the Mississippi, and from there down the river becomes very busy with large marine vessels, barges, towboats, and service boats that keep the bulk materials industries moving. Hundreds of industrial terminals, and daily passage of multi-hundred foot vessels.

Travel for a homemade vessel, especially overnight, could easily be fatal.

We'd hear reports from rivermen on the radio that one of these things had made it down, and we'd go out to try to meet them. We'd inspect the vessel to make sure it was legal; if it wasn't we'd show them off the river and give them a ride to town to await whoever might come for them. If it was in legal order, we'd warn them about river conditions.

Interestingly, of the handful of these folks that made it down to us each year, our warning would usually suffice to have them moor up and call it a trip - they had started to notice the changing character of the river and decided the next couple hundred miles of dodging 1000ft barge tows and currents that could swallow a small boat would not be fun.

Only a few were both legal and chose to carry on. I never heard anything from New Orleans about them; I hope they made it to the City and spent the rest of their pennies on celebrating in the Quarter and sharing stories. They certainly earned it.

What happens when they run into another boat? Or the river currents throw them into the rocks and an expensive rescue operation needs to be mounted?

[0] https://archive.is/oaUF1 - NyTimes story

Another possibility, since they were two people, would be oars on the stern and bow of the vessel which allow to move orthogonally to the river flow.

Some friends of mine built canoes to paddle down the Mississippi River that summer, and encountered these two. My friends said they were in way over their head on the river and were quite mean.

You can get annoyed by incompetence and lack of determination. Sitting here in your day-to-day job where your frame of reference revolves exactly around that.

But try removing that from you head for a little while and picture these young couple doing something different and living life. Hurting noone.