Think I'd pick up a copy of Tim Holschag's fly fishing for smallmouth book and get some ideas on techniques...Then allow a couple hours to scout new spots when your on the way to or from someplace else. Believe there are some smallmouth on the Sac, L. Niangua, Maries, in addition to the James, Gasconade, B. Piney, Niangua, Elk, Shoal, and Big Sugar.. I'm familiar with the Gasconade and B. Piney...but I'm not familiar with the rivers in the Western part of the state. Chief, Wayne, Flysmallie, Randy, and SWMO should be a good source for info over there. The Missouri Smallmouth Alliance is having a get together at Gasconade Hills on June 21-23...might be a good place to meet some folks and pick their brains .
http://missourismallmouthalliance.blogspot.com/p/calendar-of-events.html