You've basically already been told that. Go to your other post regarding the Katy Trail and see what JerrySTL had to say. Between his route (taken in reverse) and a good map you ought to be able to figure it out. Portage des Sioux and Machens are only about 2 miles apart. Look at a good map anyway - there are a few places you can veer off Jerry's route onto less heavily trafficked roads.