How you travel with your rats really depends on the type of transportation you are using-- car, train, plane, etc. Drives of a few hours aren't much
of a problem. A few grapes, and or other food with a high water content
will keep them from getting thirsty (water bowls and bottles should be
removed). Anything that can fall should also be removed from their cage
for the journey.
If you're traveling by plane or train, you'll have to make sure you're allowed to take rats
with you before you board. This link provides a list of airlines that will let you fly with your rat(s):
Here is a good article on making very long car trips comfortable for rats: <http://www.rmca.org/Articles/moving.htm>