Between Rockford and Chicago, US-20 is a slow, winding, and poorly signposted alternative to the high-speed I-90/Jane Addams Memorial Tollway. It’s a leisurely route, with few identifiable attractions except for the road itself, which cruises through small towns surrounded by farmlands and lined by fruit-and-vegetable stands. The one real draw here is a mile east of the tiny town of Union (pop. 562), where the sprawling Illinois Railway Museum (815/923-4000, daily, $10 and up) displays the country’s widest range of track-based transportation: streetcars, interurban trolleys, and railroad cars, with historic engines running weekends throughout the year.