My wife and her mother have 3h 45m at ORD between flights on a Wednesday, arr 120pm dpt 505pm on United. I'm thinking they have time to ride the El to the Loop, spend a half hour or so, and get back in time for their flight. My wife is somewhat familiar with CTA and ORD. They can check their rollaboards at the ORD Hilton, perhaps. What do the Chicago experts think?