Christiansen Forest Preserve in Huxley is a great place to hike. It's a mix of grassy prairie trails and wooded dirt trails. The trails in the back wooded area are my favorite, but they're quite narrow so I recommend wearing pants. There are no restrooms at this park. After hiking today, we went to Centennial Park which is just down the road and has a playground and restrooms.
We hiked a total of 1.3 miles. I recommend starting on the east side and then looping around and finishing on the west side, which brings you back to the parking lot.
There's a great tree for climbing just west of the parking lot, which has boards nailed to it to help kids climb.