Burlington Trailways operates a bus from Chicago to Rock Island hourly. Tickets cost $35 - $55 and the journey takes 3 h 10 min. Alternatively, American Airlines and United Airlines fly from Chicago to Rock Island every 4 hours.
From Chicago, IL bus to Davenport, IA. 3 h 10 min $48. From Chicago Union Station train to Naperville, Route 59 then bus to Davenport, IA. 5 h 35 min $30. From Chicago drive to Rock Island. 2 h 55 min $21. From Jackson-Blue subway to Chicago O'Hare airport, fly to Moline airport, then taxi to Rock Island. 2 h 46 min $409.