Leaving On A Jet Plane

I have two trips coming up and would love any suggestions on things I should try and see or do. My first trip is to Chicago and while I’ve been there a couple times, my husband is going to be tattooing two of the days–so I will essentially have two days that I’ll be on my own, and would love some fun things to fill the time.
Then a bit later I will be traveling to the Portland Maine to Hallowell Maine area. I lived in Maine growing up, but this is my first time back since I was sixteen (isn’t that crazy?) We will be visiting family, but will have at least one day/possibly two to do some exploring.