Reddit mentions of The Best in Tent Camping: Wisconsin, 2nd: A Guide for Campers Who Hate RVs, Concrete Slabs, and Loud Portable Stereos (Best in Tent Camping - Menasha Ridge)

Like already said, MN state park campgrounds are likely booked solid. They no longer have first come first served sites - everything is reserved. You can look at the reservation page to see if there's anything available. I haven't tried calling a park to see if they have any late cancellations, so I don't know if that works.

Alternatives are the National Forest campgrounds and the Minnesota State Forest campgrounds from which you could do day trips to the state parks or the Superior Hiking Trail or other trails for your hiking and views.

There are also Wisconsin State Parks near Duluth like Amnicon Falls, Pattison, or Brule River.

You should buy or check out from the library a guidebook or two like this one or this one for MN or another one or other one for WI to get some ideas.

I highly recommend The Best in Tent Camping: Wisconsin, which has not just useful overviews for most of the State Parks (and some County Parks, too, I believe? I don't have the book on hand right now) but also gives specific tips on what campsites in those parks are the best. Hugely helpful. There was also a Flickr album with pictures of those sites floating around last summer when I was looking; I'll see if I can dig it up.