Franklin Falls, off exit 47 from I-90 near Snoqualmie pass, is a beautiful hike! It’s pretty easy though, and barely got my tongue hanging. It’s about 2 miles round trip, a slight climb, but not too steep… and wow is the trail ever maintained (it even has steps!).
I’d call it a city-person’s walk in the woods — it’s picturesque with big trees, a gorgeous river and a spectacular waterfall at the end, but it’s close enough to I-90 to hear the traffic still, and many points along the trail is a paved road. I never saw a car travel that road, but it still took a little of the woodsy-ness away from the experience.
The parking area requires a Northwest Forest Pass, so don’t forget to tell your owner to pick one up!