Service Creek Campground is a tiny little spot off the side of the road at a bend in the John Day River, and your tent will not be far from either the river or the highway. Just six river-side campsites with firepits and picnic tables and a reasonably new vault toilet.
Basically car camping. You've got to haul your stuff maybe 100 yards to the most distant sites, but you can always see your car. And you can always hear the highway, though you tell yourself it's the gentle sound of the river. Beautiful hills to look at and the fossil beds and painted hills are an easy drive from here. Probably a fine place to camp if you came for those things. Maybe not worth a long drive if you're just looking for riverside camping.
We had three dads and three 10 year old boys and the river provided plenty of entertainment. A few trees gave hammock options and our metal detector allowed the boys to find a lot of old junk just under the surface dirt of the campsite. Looks like there's an unimproved boat launch too (read: rocky beach).