I think it's easier to solve the "too cold" problem than the "too hot" problem. FedEx certified people ship with these wonderful heat packs & I plan to buy a big batch of them for winter.
Also, if it's just your power that's out, and you only have 1 snake, you pop him in a small plastic tub with holes & LEAVE. Last winter my plan was to go to a hotel if it happened, because I only had 3 snakes, and I was just going to nest 3 tubs, bag the snakes & drive until I found a room.
Edit: Does anyone here know whether the cool packs for shipping would work for summer heat & no AC? Because I could buy those too.