For what it is worth a book "SAILING UPHILL" Author: Sam Mckinney, Publisher Horsdal & Schubart, chronicls one fellows adventure sailing accross the continent. He went up the Columbia
& Snake then down the Missouri.
It did not sound like a lot of fun. In fact it took him 4 summers and 3 boats. The last one was, for good reason, a glorified raft that only drew 4 inches of water
If you really want to cross by water
, under your own steam , may I suggest a canoe or kayak
? (and carry LOTS of bug spray!)