well i'm no expert, but when i need to travel with my little girl i put her into her travel cage(a rubbermaid container) with a towel on the bottom and a hide for her. i keep the heat up in my car, place the cage on a pillow in the passengers seat to make it a little less bumpy and then take some of those medical heat packs and place one under the rubbermaid container on one side and replace them as they cool off.
i have had no problems yet with her and she is always warm and happy once i get to where i'm going and which is about a 4 hour drive. i also try to not travel with her when she has a full belly cause i don't want any regurgitation so i always feed her 2 or 3 days before i travel. but once we get to where we are going she has no problem eating the next day for me, she is a '03 baby and loves her baby rats.
hope this helps 
~dana~