This is one of those "blink-and-you'll-miss-it" spots off of the highway.  I was driving by and took a chance, and I'm glad I did.  I managed to snag one of the last of the dozen or so campsites during the week of Labor Day.  Calf Creek runs through the middle of the campground, and about half of the campsites have direct access to the water.  It's almost like having a pool in your backyard.

The rearmost sites require you to ford the creek, so if you have a lightweight or a low-clearance vehicle like mine, you might not want to chance it.  Lots of folks use the campground road to access the hiking trail, so be aware that if you camp before the ford you'll see a ton of foot traffic during the day.  The canyon is pretty steep and that has the effect of making it chilly in the morning until the sun comes up over the rim (which happens later than you think).  Very chill staff and a quiet place to spend the night.