Wickiup Hill Learning Center in Linn County (just outside Cedar Rapids) has a great indoor area and a great nature playscape. The indoor areas follow the adventures of two kids who travel on a magical raft. You read one chapter at the start of each area to gain more insight as to what life was like during the time period.
After checking out the indoor exhibits, head outside to the nature playscape which is just a short walk away. It's a large area, with a mud kitchen, water play area, sand play area, hammocks to relax in and a zipline too. Between the nature playscape and parking lot is the trailhead for the Wetland Trail, which is worth checking out.
