Ah! Lovely to see fellow Minnesotans, even though I live in Massachusetts now. This is making me want to do a shoot in MN!
Mine might be fairly obvious, but... the sculpture garden at the Walker. I used to go there all the time and even had some of my senior pictures done there. There's a great variety of space--the greenhouse/its pond, some of the weird structures, peaceful pathways, and of course that great platform swing.