In my opinion, a sailboat on the Missouri with a small motor is not wise. Coming from the Kansas City area, the current is way too strong. The first dam is at Yankton SD. Above that the river slows down and widen's out. From Yankton to the Mississippi it can be very dangerous, especially in a sailboat with a small engine. There are very few marinas or ramps, and a lot of snags along the way, and if you get into trouble, your on your own. The Missouri River is nothing like it was during Lewis and Clark's days. The Corp of Engineers straightened it and it runs fast with very strong currents. I watched big power boats making their way into the marina at Sioux City Iowa. You could see them fight the current. Have you thought about the Mississippi River? Check out a Google search on the Alton Pool,(just north of St. Louis). I lived on my sailboat there for 6 months years ago while on business there. HAD A BALL!!! Can't wait to retire and spend some time again on the Mississippi.
Don