I have a question. When will you be coming and do you have access to a car? If you are coming during nice weather (pre-Halloween) and are driving, I actually suggest that you go to the Chicago Botanical Gardens instead. The gardens are open year round and are fantastic. The have a Walled English Garden, Japenese Islands, Sensory Gardens, Vegetable Gardens, Handicapped Gardens, etc. etc. You could easily spend an entire day and never see the same area twice.

They have tram tours and green houses as well.

http://www.chicago-botanic.org/