I would say, snake in pillow case, in small styrofoam cooler, with other cushioning if needed to stop impact from the drive (sudden stops etc.), and heat packs/hand warmers. If you wanted to be sure you could set up the travel cooler with the heat packs beforehand and then check the temp inside the cooler with a temp gun etc to make sure it stays above 75f. Obviously also don't feed before the trip, if you keep track of how often your snake defecates then try to have them defecate right before the trip so they don't go while traveling. You could try giving them a soak in warm water beforehand to encourage defecation and also hydrate them before the trip. Good luck!