Willis Creek is the most known of the two. It has a large parking lot, is family friendly, and has some sculpted narrows, and follows a creek. I enjoyed the hike, but the narrow sections were fairly short- interrupted by wider areas. There were also people on horseback that rode through in several groups.
A mile further down the Skutumpah Road is Bull Valley Gorge.
I think it's definitely more awesome. Several points had logs we had to downclimb.
The old jeep lodged in the slot, just below the road is definitely cool!
Time Needed: Several hours
Kid Friendly: Willis Creek, Yes. Bull Valley Gorge, older kids.