FYI - It is not widely known, but the Grand Marais municipal campground has a row of tent sites for hiker/bikers. Can't be reserved, they are available first come, first serve to those that show up. $25.75 plus tax, listed as Drop-In at this link:
https://www.grandmaraisrecreationarea.com/rates

If you got there and they were all full, most likely by SHT backpackers, you probably could ask one of the campers if you could share and get a spot for a tent that way. I am not aware of any other hiker biker sites like that along the north shore.