A recent report from a spotting trip to Chicago O’Hare gave a bit of information about the Hilton Hotel here. This is the best option for spotting hotels in Chicago, and can allow you to log most movements from the right rooms.
The reporter stayed in room 10080, and claims the staff were very helpful in giving him a room with airport views.
One note was that the corridor, where the ice machine is located, has a window with looks over the cargo ramps. So be sure to make trips there from time to time.