In the Model S and X you can run the climate control when the car is off. Some people have made signs to put in the window on hot days when they leave and animal in the car explaining that the A/C is on and the animal is in no distress.
Bjorn Nyland, who has a lot of videos on YouTube on his channel TeslaBjorn camps in his car frequently, though he does live in Norway. He also has a thread in the videos section of this forum. If you have any questions about the logistics of camping in a Tesla, he can probably answer them.