I live in Chicago now, but I'm moving to Portland at the end of the summer. I've only been to Portland for one night, so it's overwhelming.
You can actually have a real estate agent search for you. They charge the owner of the apartment, so it would be free to you. Proximity to public transport (CTA) is really important. Winters here in Chicago can be brutal at times so you'll want to spend as little time getting to the bus/train as possible. I believe all Chicago universities offer university students reduced priced CTA cards. If you have questions about Chicago, feel free to message me!