I did this from CO to the east coast a few years ago. I found a couple of old coolers and drilled an air hole in each of the four sides and a few on top. I filled water bottles with warm water and put them in the bottom of the cooler and covered them with shredded paper. Placed all my snakes in snake bags and loaded them in the coolers. Between the cooler insulation and the shredded paper over the water bottles it held temps pretty good. I would redo the water bottles every morning before leaving the hotel. I was traveling with three kids and car trailer loaded with two cars so it took us about 3 1/2 days. All snakes arrived in good shape which is better than I can say for my nerves.