The DOT has a public meeting video and PDFs for changes at IA 27/58 at Ridgeway Avenue and US 20. The Ridgeway intersection and the diamond interchange are not going away. The biggest change is the addition of a left-turn lane and stoplight for southbound 27/58 to eastbound 20. This is the turn for the Avenue of the Saints.
This is the only place along the Avenue that the Avenue traffic must turn left. The most significant other change in direction, at I-35 and US 18, is a cloverleaf with collector/distributor lanes.
US 218 through Waterloo is an option, of course, taking the southbound 218-exit-from-itself loop at the north end of 58. But that way, too, involves stoplights. Following IA 27 there are only three intersections now: 20, Ridgeway, and Greenhill Road.