The Arkansas River is a great flathead hole, as are some of the other waters mentioned. However, you might want to look up some advice from Keith "Catfish" Sutton. He probably knows about as much as humanly possible about Mr. Whiskers - whether he be a madtom or a big blue. I know he has mentioned Millwood and the Little River below the dam there. If you want to learn more, you might want to see if you can find one of his books.