As someone who grew up along the Mississippi and comes from a long line of boat people, I think its cool that people have a renewed interest in traversing the Mississippi, but I gotta say some of yall are have really naive, romanticized ideas about it. If you wouldn't take a clown car out on the interstate, you probz shouldn't take some shitty craft you hodgepodged together with super glue in a couple days out on the Mississippi. The mighty Mississippi isn't some tiny pristine stream in Pennsylvania or Virginia. Can you build your own craft and sail from Minneapolis to NOLA? Sure, but as the Rockaway Armada crew found out the hard way, it isn't as simple as throwing some logs and milk jugs together and jumping in. You gotta have a solid craft and know what the fuck your doing.
And the Mississippi River in Winona or Minneapolis/St. Paul is not the same as the Mississippi in St. Louis or Memphis or NOLA. The water is littered with tree branches lining the bottom once you get to St. Louis, and the currents double in strength once you get to the Ohio River convergence at Cairo, IL, and by the time you get north of Memphis, the river gets so wide you could easily think you were in one of the great lakes (there were no Mississippi river bridges south of STL for decades because it was considered too wide to engineer) and by the time you get to Louisiana, the waters become so muddled and swampy, travelling in a small craft without capsizing or scraping the bottom of your boat is near impossible.
PS: And no, you cannot boil and drink water out of the Mississippi. There is a reason most towns and cities along the Mississippi don't get their drinking water from the Mississippi.