While the campground itself was nice, with spaced out sites for privacy (larger campground than I expected), in August the water was so low that we went to next door South Twin Lake for boating and swimming. We weren't the only ones-- it was packed!
Smith Rock is a worthwhile destination, even if you only have a day. I'm not a rock climber or very fit hiker (so misery ridge was off the table). There were still great trails to take advantage of along the river, that were less trafficked than the misery ridge trail as well.
Our experience here was a quiet one, and we chose the campground for its proximity to Smith Rock, which I had never been to, and as a dark spot from which to watch the Perseid meteor shower. In those two ways, the campground worked pretty well! Unfortunately, the lake was in the midst of an algae bloom, so not ideal for swimming and we saw no one on the lake. There was also a fire ban in place at the time.