This was a great hike for adults and kids alike. We had four adults, two 4 year old boys, a 3 year old and a toddler along.
We somehow missed the sign at the parking area to the falls overlook, so we never actually saw the waterfall. But no matter. From the trailhead, we started down the trail. It was steep, with switchbacks and some slippery rocks. The boys had no problem with the descent, but the just-turned 3 year old ended up on her father's shoulders.
Once we reached the Quilcene River, we headed upstream about a mile or so. The children feasted on red huckleberries. Eventually we found a brushy trail down to the water where we stopped for lunch at one of the loveliest lunch spots I've seen - a deep blue-green eddy, a rocky bar for throwing rocks and a small noisy rapids all dappled in sunlight through the old growth forest.
Although the guidebook describes a loop back up to the parking lot, the side trail we tried on the way back seemed to head off in the wrong direction with no switchback in sight. With four children along, we felt the stakes were too high to continue going on that route. So we returned the the main trail and headed back that way.
This trail is not on a Green Trails map. If you can get your hands on the Mt. Walker USGS quad, it would be beneficial to have along.