Hiking Killbuck State Park - is it worth the drive?

Thinking about taking the fam (5, 8, and 11 year olds) out to Killbuck next month. We're in Columbus so it's like 90 min drive. Reviews seem mixed - some say it's gorgeous, others say it's crowded and the trails are boring for younger kids. Anyone done it with young kids? Which trails actually work for short legs? Also how early do we need to get there to find parking?