when i transported my new baby dragon i went on a 1 hr trip home and i just kept him in a pet carrier with some crumpled newspaper so he had stuff to hold on to (the breeder suggested i do that so he doesn't slide around all over the place). we kept the AC off and had him under the light so he was just hangin out under the sun.
i'm thinkin that if you're gonna get stuck in traffic coz EVERYONE will be travelling (that's what's gonna happen with me.. leaving early 2 avoid traffic! woot!) and the temp shouldn't go too low if the weather is cold, then maybe you can have a heat pack around the outside of the critter keeper. if you're travelling with someone else, the passenger (you or the other person) can hold the critter keeper steady with the heat pack around it.
that's just my opinion though 
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0.0.1 Bearded Dragon (Cookie Monster)
1.0.0 Crested Gecko (Vas-D)
0.0.2 Fire Bellied Toads (Norman & Forman)
0.0.2 Goldfish (Lenny & Carl)
1.0.0 Black Lab / Pit Bull (Mikey)