I would recommend hitchhiking through northern Minnesota, Duluth, and the Upper Peninsula via Bruce Crossing. Duluth is pretty fun. I guess you are from Minnesota. I hitched through North Dakota and Montana and it was fucking crazy, like gay ranchers constantly trying to hit on me, and everybody else has some problem with travelers. I was stuck in Bismarck for 3 days.
Unforuntately Minnesota is surrounded by red states so I think it would be a tough time overall. Maybe I would hitch from Minneapolis through Iowa to Kansas City, and then to Colorado.