Make the Chi-Town layover fun!!!
1. Take the 4 hour layover.
2. When you get there check the bike in for the next train as luggage -or- go to the Metropolitan Lounge and check in (Worth the $) ask them to check-in the bike -or- take the bike to a nearby first class hotel and ask the bellman (Tip needed for this idea) to check the bike into the luggage room until you get back.
3. Go walk around downtown Chicago. Get a deep dish pizza. Walk to the Art museum and check it out. Go to Grant Park and take your picture in front of the Cloudgate statue ("The Bean" to locals), Take the architecture boat tour on the Chicago River. Go window shop on the Michigan Ave. Go check out the historic rocks, bricks, embedded in walls to Tribune building. Buy a Cubs or Soxs or etc.
4. GO back to reclaim your bike and get on the train to Milwaukee.
OPTION #2
1. Check your gear except your bike
2. Take your bike and ride Chicago's scenic Lakefront Trail, an 18-mile paved path that follows the Lake Michigan shoreline on the city's eastern edge. It extends from Ardmore Street (5800 N. Sheridan Rd) on the north side to 71st Street (7100 S.)
3. GO back reclaim your gear and get on the train to Milwaukee.
Have fun!!!!!