Beautiful and super quiet. The Black Canyon Campground was recently renovated and facilities are great. GPS ends a few miles just before the campground (near the Ten Thousand Waves Spa), so just keep going "straight" along the road to get to the campground.
Learn about North American history, people, and culture between ~600CE to ~1300CE. Drive along to see each of the structures, stop and send a postcard from the park, and best yet - walk, climb, crawl through a historical, cliffside dwelling!
If you're up for it, skip the super easy drive-up arches and do the Devil's Garden Trail... the whole thing. Be prepared to work hard and take a few hours to do the whole trail (including the Primitive portion). Take lots of water and make sure you're good with heights, sand, and wind. The Dark Angel spur was a bit of a disappointment, but around 1/3 along it, there's an amazing view on your left. This trail is not for the faint of heart.
Mid-day stop quite literally in the middle of nowhere (near the Visitor's Center, not Halls Crossing, but this is what Roadtrippers has). Swim and bask in the sun in the middle of the desert.
Then take the cross country drive (if you have the vehicle to do so) to Bryce instead of the highways. Follow BLM 12000 and what Google Maps will tell you to do (set it up before you leave the Park as you will lose signal). The views are beyond spectacular and you'll drive right through Escalante enroute to Bryce. Minimal to no signage, no road striping, 14% grades, tight corners, gravel/dirt roads, super tight switchbacks... not for the faint of heart. Very helpful to have a rally-style driver and separate navigator.
Beautiful. Relatively easy hiking along the major tourist areas. Very cool rock formations. Be prepared in May for snow... bring clothes for all weathers.