420 miles, 6 hours of I-15 South. One real lunch stop in Beaver, UT (the natural midpoint), one quick gas stop in St. George if needed, and you're at the rental by 7:30 PM. 75°F clear — easy driving weather.
Take the minivan — way cheaper than UberXL with car seats. ~22 min to Spy Ninjas, free parking on site. Wife is the driver. Leave Spy Ninjas by 12:30 PM sharp to make Sphere by 1:30 PM.
Take Uber for parents — saves the casino-garage walk and parking hassle. Three indoor, AC-cooled stops on the Strip. Bring cardigans for the parents (Sphere keeps venue at 68°F).
2 PM Wizard of Oz at Sphere. After: pool break at the rental, then optional evening on the Strip — Circus Circus, High Roller, Bellagio fountains.
Long day — 250 miles round trip, but this is the unforgettable one. Glass bridge over the Grand Canyon, 4,000 ft straight down. Leave early to beat the heat AND the crowds. Plan for ~10 hours total. 100°F in Vegas, slightly cooler at the canyon.
Reverse of Thursday. Eat the leftover groceries, pack methodically, depart by 11 AM. Lunch in St. George, gas in Beaver, home by 6 PM. Mostly downhill from Vegas to SLC (gravity helps).