There is some incredible beach camping to be had at Strawberry Point. The best spots are located immediately south of the point on the beach and tucked into the giant piles of driftwood. There is a freshwater creek about 1/4 mile south of Strawberry Point. There are also other fresh water sources on the way if you access the beach trail from the La Push area. It's National Park so bear cans (for racoons ) and permits are required. I would bring a rain shell even if the weather calls for clear skies.
Mosquito creek is accessible from Third Beach LA Push (North) and the Hoh river/Oil City from the south. There is room in the trees at Mosquito Creek for a few medium sized groups. The camps lack privacy and are a hearty few hundred steps up from the beach. There is a primitive pit toilet in the trees as well. Where the creek meets the Pacific there is another decent place for maybe 6-10 tents. Please pay attention to tide charts before you embark on this Trail. It's also in a National Park so a permit and a bear can (for racoons) are required.
If you are looking for a quiet lake in the trees with the option of a picturesque hike…this place is for you. We stayed on a warm Friday night in July and had the entire lake to ourselves! Bring bug spray because the established camp sites are in the shade with the the mosquitoes. There is also a primitive pit toilet which is slightly better than digging a hole. In the National Park so I would recommend consulting with the local Ranger about a camping permit (White River Ranger Station).
This place is beautiful with many different options.