The way I move fish (not tanks) is put them in a plastic bag as I get them from the LFS and put them in a box them half way on the trip I open the bags then continue, and when I get to the place, I usually take a bucket with me and when I get there I fill the bucket with water and place the fish on top with the bag open.
However, if you have de-chlorineator with you, you could de-chlorine the water when you get there if you have coldwater fish, if you have warmwater fish you can ad some hot water and bring a thormometer with you so you can check the temperature.