Use sunset as your turnaround alarm.
Two slot canyons on one loop is the appeal, and both of them stay walkable, which is what makes this doable with kids who would bail on Spooky. BLM calls the full loop about four hours with a few scrambling sections, and the trailhead has a real parking lot, vault toilets and a kiosk. Leashed dogs are allowed, which is worth knowing before you leave one in the car. The flash flood potential is described by BLM as extreme, so read the forecast for the whole Swell.
Utah's best family slot canyon loop, near Goblin Valley.
Heat note: desert country - in summer start at dawn and carry more water than feels reasonable.
2 liters water, trail shoes, sun layer, snacks, small first-aid kit.
Make it a weekend: Fruita Campground (Camping, 32 mi) · Millsite Reservoir (Fishing, 41 mi) · Singletree Campground (Camping, 45 mi) · Fish Lake (Fishing, 49 mi)
More hikes nearby: Goblin Valley Free Roam (Hike, 6 mi) · Hickman Bridge (Hike, 31 mi) · Grand Wash (Hike, 31 mi) · Cassidy Arch (Hike, 32 mi)