Olympic National Park’s [1] Mora Campground (open year-round, $10) is a pretty in-the-trees place to pitch a tent. Check with the ranger station here for summertime naturalist programs and nature walks.
RV owners can pull their rigs into Lonesome Creek RV Park (360/374-4338, $30–35 full hookups), which offers many sites with ocean views. RVers can also park at nearby Three Rivers Resort (360/374-5300, www.northolympic.com/threerivers [2], $18 with full hookups).
Links:
[1] http://www.moon.com/destinations/washington/olympic-peninsula-and-the-coast/olympic-national-park
[2] http://www.northolympic.com/threerivers