If you have much of a vehicle journey, putting the bagged snake into a styro-foam shipping box or "ice chest" (no ice!) will help protect from excess heat from the
sun* if you get stuck or stop for lunch. Don't risk your animals, plan ahead for what may go wrong. They are stuck & have no way to call for help...they just die.
*I can remember a sad thread years back on another forum, a member lost his favorite snake that was only bagged & put on the floor of his truck for a long ride.
The floor had little insulation from the engine heat and the snake died from heat exposure...he was barely alive on arrival & passed quickly, nothing he could do.