"Officially called the Olympic Discovery Trail Adventure Route, locals call this point-to-point trail the OAT. It's a 25-mile point-to-point singletrack trail from Hwy 112 to Lake Crescent featuring long inclines and descents along the way. The first 3.5 miles are mostly uphill until the Living Room, where you're rewarded with a stout wooden bench and great views of the Bailey Range to the south.
From the Living Room, continue west for more rolling hills and switchbacks, deep mossy forest, and views of the Strait of Juan de Fuca and Vancouver Island, Canada, to the north. Around MP20, you'll hit a gravel logging road; take a right, follow it all the way to its end, then turn left and continue on to Lake Crescent."
Note: The "Olympic Discovery Trail" is something different, and extends ~21 miles from the west end of Lake Crescent.