The Fossil & Prairie Park is such a cool place to explore. I highly recommend visiting. The Center is open from 1-4 pm and has some interesting displays. There are also restrooms inside the building, as well as packets available which include maps of the park.
The old quarry has some very steep paths, but my 6 year-old twin boys did ok navigating their way up and down. I was surprised by how easily we found fossils everywhere we looked. Buckets are very helpful in collecting fossils. If visiting during warm weather, don't forget water and sunscreen.