Not sure if it’s been mentioned but anti freeze washer fluid. You can’t get it in SoCal. Get a bottle of 90% isopropyl alcohol and add to the fluid. I made the trip years ago in a grand Cherokee San Diego to Oklahoma in the winter and washer fluid froze before flagstaff and stayed till back...
Loaded up and took the kid to college. Left SoCal at 10:30 p.m for 6:30 a.m check in. All night drive through the desert up hill into the wind on 37s. The things we do for our kids. Worth it.