We have stayed at CP something like 4 times now and generally have greatly enjoyed it. The campground is at 9,500 feet (or so) of elevation, so if you're not coming from elevation you might have trouble sleeping great the first night or so (or maybe this is just in our minds!). It's roughly a 9-mile, 15 minute drive into the town of Buena Vista, and less than a 5 minute drive to the popular Denny Creek and Avalanche trailheads.
We have tent-camped here, but our last two stays have been with a 20 foot travel trailer and we've had no issues finding a site even though showing up without reservations. There are no hook-ups at all, and unfortunately there's not even a water source except for the beautiful creek running adjacent to the park. It feels like maybe the campground is at the bottom of the National Forest maintenance list, as the roads (potholes) haven't seen a grader in a while. If you're parked or are camping near the road, you're going to get dusty as unfortunately folks tend to speed along the roads even with the potholes. There are water spigots, but they're not functional, and haven't been since at least 2020.
We've never had a hint of cell coverage (T-Mobile) while staying there, as you're kind of recessed between the mountains. But if you climb Mt. Yale from the nearby trailheads you pick up a good signal near the top as you gain line-of-sight down into the valley where the antennas are.
This is a nice, off-grid campground if you're really prepared to be off-grid. We will definitely stay here again the next time we're around Buena Vista.