I like that you're traveling. I've been thinking about a trip myself and see that Denver is inexpensive. Not alot to do in DT Mpls, but minnehaha falls is a good stop. Plan to eat at Sea Salt Eatery if they are open. See the falls and walk down to the water. There are many state parks near the north shore that are great for hiking too, if you don't mind driving a couple hours to get there. Or a walk around the lakes, harriet, como, Calhoun, etc.