Take some dry clothes with you in something that will keep them dry, just in case. What part of the Niangua? Definitely crawdad crankbaits. Also a jig under a float. In line spinnerbaits (Mepps, Roostertail, Blue Fox, etc.) will work too. I always fish a tube too, but like others have said, that's often best done standing still. Have fun. There's a group of us going out together in May, the Niangua is on the short list. The one we go to depends on if the rain we've been getting lately keeps up.
If you're fishing below Bennett Spring, you can also fish for trout but I assume you know all about that.