A time machine. Spoiler Let the lady do the driving EDIT: Jack Daniels often helps me travel days into the future. Use as desired for moderate time travel.
There are signs in Arizona advising drivers to turn off their air conditioners, for a reason. I've had this problem in brand new rental cars going from Houston to Colorado. You are going through worse conditions. You go 85 mph in the desert in the middle of a summer day with your air conditioner on, you better watch your temp gauge.
I drove one way from H-Town to Cali and I definitely would not have wanted to make a drive back after only a couple weeks and I didn't have kids. I think you should do the Friday night thing IMO because it is going to make the driver easier with kids. Either way be prepared for sheer boredom from San Antonio to Phoenix.
Actually, the weather in the west is going to be pretty nice this weekend. We spent the past few days over 100F here in Vegas...but are expecting low 80's for the weekend. LA is going to be even cooler. I guess the last cold/cool front of the Spring is making its way through now and it's crazy windy here today. @droxford...be careful in the mountain overpasses...the winds can be pretty nasty for high profile vehicles (I know minivans are nowhere near the profile of a big rig, but they still get pushed around quite a bit). Have fun and be safe! I'll be trekking from Vegas to LA this weekend also to hang at the in-law's house.
I've done the drive three times and completely agree with the SA to EP stretch is awful. I would recommend trying to leave at some time to do that part of the drive during the day. While you have faith in your vehicle given how empty that stretch is you wouldn't want to take any chances breaking down somewhere in the middle of the night far from help or where you have to wait until daylight before someone can see you.
first aid kit, flashlight, mirror, extra batteries, paper towels, aaand paper towels. Man, the summer between fifth and sixth grade my parents decided to take us (I have a younger sister also) on a road trip from houston to san jose. Went west to arizona, then north through utah and nevada up to idaho, west to washington and down through oregon to san jose. WE DROVE THEM INSANE. Also, we took out the middle seat and lay down sleeping bags and pillows all around and lay on the floor and played games. one of you could be playing with your daughter while the other drives. it's safe, but 1993 safe, not 2008 PC safe. lesson: the more the kids sleep the better off you are.