5 days. Still trying to figure the rest. Wedding is in the burbs. I would like to see the sights, the bean and park. Deep dish pizza. They have a circle line boat tour kind of thing like Manhattan?
So first you’ll want to decide your base- better to stay in the city than deal with the 45 min train ride in from Wheaton or Naperville.
I’d look for a hotel on the Near North side- north of the river and South of Chicago Ave.
Walkable to everything.
Sights are obvious- Milennium Park, Navy Pier (majorly touristy, but a great view), the Riverwalk, Magnificent Mile, etc. Museums - Art Institute, Field Museum, Shedd Aquarium are all kind of together in a beautiful museum campus.
Come up to my neighborhood in the Gold Coast and walk the streets to see 1800s brownstones and mansions. Ride a rental ebike down the lakefront trail- a 20 mile trail that gets you access to all kinds of sights, including the free Lincoln Park Zoo. Learn to take the El (subway) and you can even more mobile to visit the West Loop (younger hip crowd- fantastic dining), Wrigleyville (there should be playoff baseball happening) or some of the great neighborhoods (Lincoln park, Logan Square) where restaurants are cheaper and more interesting.
The best thing to do is to get on a an architecture cruise- 45 min in the river with a great docent to point out what you’re seeing. The best is run by the CAC, but any one is good. A boat on the lake is nice too- we like the Windy- a sailing ship.
Restaurants are plentiful and great, and a bit more pricey in River North. Deep Dish pizza is always a controversy, but I’d recommend Lou Malnati’s, Uno/Due, or Labriola. Do try an Italian beef- Portillo’s or Buena are both nearby. Chicago dog at Portillos, Devil Dawgs, or the Kim and Carlos’ stand outside of the Field Museum.