While yes, this spot is technically open to the public, the Lewis River Campground Community of Christ (unsurprisingly) feels much more like a summer or church camp that the same groups go to over and over again each year. Slightly run down cabins but with some nicer, newer buildings as well. Available to rent for events such as family reunions, I tend to prefer spots you can swing by and grab a spot last-minute among other campers, and this is not that at all.
Just off the road and not far from the Lewis River, if you're looking for more-campground/less summer camp, try any number of other state and forested campgrounds in the area.
A church camp near Moulton Falls near Washington. The camp has a few RV pull-though spots, but the main part of the campground involves a number of “cabins” that you can only use as part of a large group gathering. Nice playgrounds on site, soccer field, TP, and the like.
Cabins look a bit drab/well loved, depending on your point of view.