I live about half an hour away from Rolla but i dont know that area much. I heard the road between there and Salem is pretty curvy and a lot of roads out around salem are supposed to be really curvy also. Would be your best bet as far as i know.
if you jump over to the FocalJet they should be able to give you some decent roads. they tend to have a spring and fall set of meets in mid-MO to go on twisties and the like... this year they are just bogged down with JetFest...