You could probably even use a soft-side suitcase to keep your bagged snake in for a while. The zipper type will allow a bit of air-flow too.
An actual cooler is optimal though because many places you end up in will be running air conditioning & it may be out of your control. People you stay with are
likely to put their own comfort ahead of your snake's comfort...go figure?And you have to pay attention to temps getting too hot inside a car...if you have
to park for a pit-stop, etc. Coolers (ie. insulation) just add safety.