So I'm from Duluth and am more than familiar with the North shore. In June you can expect flash floods only, to hold water in the creeks, otherwise the season is already over...await a gnarly thunder storm. The St. Louis is dam released, and will still have decent flows. The upper St. Louis is class III and has one class IV drop... and is generally a booze cruise or beginner learning grounds
Below the Dam and into Jay Cooke state park has more Class IV/V goodness. And below the "swinging" bridge is the best fun... much class V beauty (see pic below). Lap it and smile.
Check out my blog for pics of the entire N. Shore creeks and the St. Louis (use the search feature): The Adventures of Burgess