As for the zoo which one? We have two.

Lincoln Park Zoo is not the better of the two zoos and the rape you for parking but it is free.

Brookfield Zoo is bigger with more exhibits and stuff. It cost money to get in and isn't actually in Chicago but is in Brookfield, IL. I think they may charge for parking also but it is far more reasonable.

Also what do you want to do if it rains? Rain is looking less likely but I never write it off.

Also you would like to think that there is enough time to go to a museum after the Zoo but museums close at like 4 in the afternoon...or close to it...so it really isn't happening to do both.

As for Museum I vote for the Planetarium, Aquarium or Museum of Science and Industry.