I don't think you can find a more pleasant city to visit on a lovely fall day. We stayed at the Marriott Courtyard in the center of it all - thanks to our successful Priceline bid. We found that bidding on Priceline is the great way to go for low rate (assuming the city isn't sold out due to a special event, etc.). I took the River Architectural Tour which I thoroughly enjoyed and then walked along Lake Michigan where you can actually walk or bike on a path for 26 miles. We also went to the newly remodeled Art Institute of Chicago (free on Thursday evenings). The next morning we enjoyed our swimming pool overlooking the city and walked up State Street. We then walked to Union Station where we caught the MegaBus for a long ride home - it was went fast and it was rather relaxing.