Hmmm I know rats are more social and intelligent than the rodents I have... but I sometimes travel (2:30 hour trip) with my gerbils hamsters and mice. What I do is put them in those small plastic cages... all animals from a cage together (the size of the travel cage is different depending on the size and quantity of animals). I put in a bit of food and some greens (for moisture) but no water bottle (cause it leaks with the movement). I notice that the first 15-20 minutes they are crazy, running around and digging and just nervous. Then they calm down and go go to sleep.. and (unless waken up by a big bump in the way) they sleep the rest of the way. I guess that for rats it would also be a good idea to add a familiar house or toy (something that they had in their cage. I can't think of anything else.