A fairly easy mile or so from the trailhead, Wahclella Falls offers a scenic hike and a huge roaring waterfall. Plus a cave and rocks to scramble over, though I didn't tell you that.
This trail is currently closed in the wake of the 2017 wildfires. Restoration is in progress.
If you find any factual innaccuracies in this post, please email me via richard at thingstodoinportland dot org so I can fix it for everyone. Thanks in advance!
Go east on I-84 to exit 40; take a right and the trailhead is right there at the end of the parking lot. [Google map].
This thing to do was suggested by
Best Hikes with Kids: Oregon – thank you!