We arrived mid-Saturday Labor Day weekend and less than half the sites had been claimed. It was perfectly positioned between our weekend activities: Painted Hills and Lucky Strike Mine. By late Saturday most (if not all) sites we're claimed.
The sites are large and well looked after. Bathroom was surprisingly clean and not smelly. Camp host even provided a large tank of water (but I wouldn't count on that).
Pro Tip: drive 20min East to Mitchell, Or and get a pint at Tiger Town Brewing. Great people, food and beer! We packed camp dinners for both nights, but ended up at Tiger Town every night because the atmosphere was so good.