We always begin around the Foster/Montrose Beach area (seen below) where parking is abundant. We leave our suburban homes after the morning rush hour and drive to the lakefront, bike south, and return by 2pm to beat the evening rush hour.
If possible, avoid summer weekends when there are so many people that riding is very slow and sometimes dangerous. You must stay constantly alert for people on the trail and crossing the trail, most of whom don't bother looking to see if a bike is approaching. In the photo below, the trail is nearing downtown Chicago.
The Chicago Bike Path passes right alongside Navy Pier, and bike racks placed there allow bikers to park and walk the mile long pier and grab lunch at one of the many eateries available on the pier. Or if a snack is all you want, plenty of kiosks offer ice cream, pretzels, etc.
We also cross Lake Shore Drive at one of the traffic signals and head over to see Buckingham Fountain and Millennium Park with its nearby "Bean" sculpture by Anish Kapoor, officially named "Cloud Gate." Both of these, pictured below, are highlights sought out by all visitors.
Just south of these sights is the museum campus. The photo below was taken from one of the museums, the Shedd Aquarium. The bike trail circles around the aquarium and gives views looking north at Monroe Harbor and Chicago's downtown skyline. The Willis Tower (formerly the Sears Tower) which was the world's tallest for 25 years after opening in 1973, dominates the sky in the center of the photo. South of here, the trail passes Burnham Harbor, Soldier Field, and McCormick Place as it heads south to Jackson Park. A number of former Nike missile bases (protection for Chicago during the Cold War) were turned over to the city years ago and have been converted into public park space.
In the photo below, we are heading north back to our vehicles, but a rest stop offers another dramatic view of the downtown. The tallest building sporting the large roof antennae is the John Hancock Building. When finished in 1968, it was the tallest building in the world outside of New York City. It is currently the fourth tallest in Chicago and the seventh tallest in the world/