If you have never experienced the true heat of Az, New Mexico, and Nevada Summers, I highly recommend against it. Dogs are not allowed on most trails in National Parks, and cannot be left alone in a car during that type of heat.
It will most likely be a miserable experience for everyone involved. If you must go, you might consider leaving your pets at home, with a house sitter. The kids will probably be ok, but the Summer is when most tourists to those areas end up getting heat stroke, or sick/ hospitalized.
The kind of heat you are going to experience is not something to be taken lightly.
Maybe consider heading North instead. JMO
