The area around Wynoochee Lake has multiple short trails leading to spectacular waterfalls. It's an ideal place to take kids for a camping trip with a little hiking thrown in.
While I have hiked to Wynoochee and Spoon Creek falls before, I had not been to Maidenhair Falls. While Maidenhair may not feel as impressive as Wynoochee and the drop is not nearly as big as Spoon Creek, I think the trail leading to Maidenhair is pleasant and the most kid-friendly. Only as you near the final steps to the falls do you need to carefully watch young children -- I ended up carrying my 1+ year-old nephew past a few places where the edge of the trail dropped to the creek and across the nice wooden bridge that overlooks the falls. My 3 year-old niece was already being carried at that point.
I should note that the trailhead can be tricky to find -- the driving directions for this hike are correct. Just make sure to park soon after turning onto the final spur road. If you get to a huge mud puddle, you've gone too far. If you reach the river, you definitely went too far. The trailhead is just after turning onto the spur road -- look to the right and you should see it. The trail is actually the Wynoochee Lakeshore trail, which travels around Wynoochee Lake for almost 17 miles.
The short .5 mile hike to Maidenhair goes on nice trail through old growth forest and is easy for children to walk on. It switchbacks a bit to reach the falls and there are a few obstacles to cross -- this time a few downed trees that needed to be climbed over.
The falls are beautiful and a good destination -- my niece and nephew were able to walk much of the trail after dropping away from the falls and cliffy banks of the creek. If you feel so inclined, you can hike past the falls and reach the river and beyond but we turned around at the falls.