Time the last feed days ahead
The preparation starts at the feeding calendar. A snake digesting a meal needs warmth and stillness, and a car offers neither reliably, so the classic outcome of feeding before travel is a regurgitated meal and a stressed animal. Offer the last feed several days before the journey, longer for a large snake with a large meal, and let the journey fall in the empty, calm part of the cycle. Fresh water before departure is fine; a snake that has drunk and emptied is a snake ready to travel.
Bag inside a box, both secured
The cloth bag is not old-fashioned habit; it is the safest restraint a snake can travel in. Turn a smooth cotton or linen bag inside out so seams cannot catch scales, settle the snake in, and tie the neck in a knot it cannot work against, because snakes explore a tied bag's corners with surprising patience. The bag then goes into a rigid, ventilated tub with a latching lid, lined with paper, wedged so it cannot slide. Two layers, both secured: a snake that escapes the bag is still in the tub, and a tub that tips is still shut.
Temperature: cool and steady wins
Snakes travel best at the cool end of comfort. A car cabin kept pleasant for its human passengers, not sun-baked and not air-conditioned to arctic, suits most species for journeys of a few hours, because a slightly cool snake is a quiet snake. The killers are extremes: a closed car in summer sun, a tub pressed against a heater vent, a boot that swings between cold and fumes. If the journey is long or the weather cold, a heat pack outside one end of the tub gives the snake a gradient to choose from, exactly as its enclosure would.
The drive itself, boring by design
Drive as if the tub were full of sleeping passengers, which it is. No handling stops, no showing the snake to anyone at a rest stop, no opening the bag to check: a bag that rustles softly is doing its job. Keep the tub shaded and level, check it only by eye at stops, and if the car must be left in heat, the tub goes with you, because there is no errand short enough to justify a closed hot car. Talk and radio at normal volume are fine; a snake reads the world through vibration, so smooth roads matter more than silence.
Arrival and the first check
At the destination, carry the tub straight to the waiting enclosure before opening anything. Untie the bag inside the enclosure or lower the whole bag in and let the snake leave in its own time, because after travel, choice is calming. Offer water, check the animal over visually for rub marks or mites disturbed by the trip, and leave feeding for a day or two once it has settled and warmed through. Before any of it, though, the ten-second job: check that your snake's KinsLe Verified QR ID Pet Profiles entry holds your current number, so if a bag ever did fail in transit, the finder reaches you by scanning, not guessing.