The Elwha River trail cuts through Olympic National Park north to south, providing a wide, well-maintained path to destinations and camps all the way to the North Fork of the Quinault River, on the southwest side of Olympic National Park. This means that you can create a hike just about as long as you can go, but Lillian River marks the furthest most day hikers will likely want to go.
Beginning at the large and well-appointed Whiskey Bend trailhead, set out on wide, well-manicured trail. Spur trails at 1.2 and 1.6 miles mark turnoffs for Rica Canyon (also access for Goblins Gate) and Krause Bottom respectively before you arrive at a three-way junction, complete with historic log cabin. You've come 1.8 miles. Take a break and check out the historic cabin, reading about who used to stay here, and the people who lived in this valley long ago. Here's a good place for a snack; it's another 2.4 miles to the turnoff for Lillian River trail.
Continue straight on. Formerly flat, your trail now begins climbing, gently but persistently. Take in the deep, lush mosses lining the trail and the trees, and listen carefully. You can't hear much. The noise is dampened by the foliage and the lack of visitors (most day trippers do Geyser Valley, turning right down to Humes Ranch at that three-way intersection).
The forest continues, and just when you think you might have had about enough, the landscape changes, breaking out into a sunny, rocky patch of trail with madronas, before diving back into greenery and descending to cross Idaho Falls. Not much further to the turnoff now!
In a half mile, look for the sign indicating the turnoff for Lillian River. The Elwha Trail stretches out ahead of you, well-maintained and relatively wide, but the Lillian River trail is much more narrow, bordered by salal, heading gently uphill.
From here, it's another 3.5 miles to the end of the Lillian River trail, which dead ends at the banks of the river after climbing to 2300 feet (you're currently at 1500, so that's about 800 feet in those 3.5 miles. Lillian River trail is even quieter than the Elwha Trail, and the forest giants are your only company. Take in the silence, and then head back. Despite the relatively flat trail, at 13.4 miles, this is a solid day's worth of hiking.