E.S.
St. Joseph, MI is very nice! It takes us about two hours to get there from Naperville. They have a really cute downtown area with lots of little shops. My kids always request a stop at Kilwin's for ice cream. :) Silver Beach in St. Joe is one of the best beaches I've ever been to! They have a great playground at the beach & a new "splash pad" that just opened last year. They also just opened a new Children's Museum right on the beach. It's small, but my kids loved it. Attached to the museum is an awesome new indoor carousel. The other nice thing about St. Joe is that it's sort of in the middle of a lot of great little small towns along Lake Michigan. You could easily drive to New Buffalo, Southaven, Saugatuck, etc. for an afternoon or dinner. Here's a link for some more information on St. Joe: http://sjtoday.org/site/
Wherever you decide to go, have a great & safe trip!