Cushman Lake Resort (4621 N. Lake Cushman Rd., 800/588-9630, www.lakecushman.com [1]) has rustic cabins ($55–135 d) with kitchens and baths; canoe, personal watercraft, and boat rentals; a convenience store, plus tent and RV sites.
Camp in one of the two campgrounds at Camp Cushman (7211 N. Lake Cushman Rd., 360/877-6770, $20 tents, $26 RVs with hookups), with loads of nearby recreation opportunities.
The Forest Service’s Big Creek Campground (877/444-6777, www.recreation.gov [2], $10, open May–Sept.) is nine miles up Highway 119. The road ends after a total of 16 miles at Staircase Campground (www.nps.gov/olym [3], $12, no reservations), just west of the lake below the Staircase Rapids of the North Fork of the Skokomish River. This beautiful Olympic National Park [4] site has year-round camping surrounded by old growth forest. Chose a riverside site for the ultimate nighttime lullaby.
Links:
[1] http://www.lakecushman.com
[2] http://www.recreation.gov
[3] http://www.nps.gov/olym
[4] http://www.moon.com/destinations/washington/olympic-peninsula-and-the-coast/olympic-national-park