Doubt school will be out in April and May. I've been through death Valley in the summer three times and all three times I've had to run the heater with the windows down to try and keep the engine from overheating. The last time I had rigged a water spray system using water from the travel trailer to spray water on the radiator and it still overheated at less than 20 mph. Waited until later in the day leaving Yosemite so the temperatures would not be as hot.. waited until later in the day leaving Yosemite so the temperatures would not be as hot. . only 118.
I agree it's the shortest way to get to Vegas but I would rigg a water system with a spray bar and a valve that you can turn on from the PU when needed using the 12 V water pump in the camper. There is a reason there are water barrels every half-mile on this route.
PS: I boiled the brake fluid on the way down when a car pulled out in front of me losing the brakes on my suburban and having to use the electric brakes on the trailer. The brakes fixed themselves when they cooled down at the stovepipe wells.