If you are travelling in a personal vehicle, you might be able to carry the fish and some filter media in a 5 gallon bucket. They are sold at home improvement centers for fairly cheap with a good fitting lid that should help keep the mess down. Only fill the bucket half full of water and don't feed the fish the day before the move or during the move. That should keep the wastes to a minimum and let the sloshing water move water across the filter media to minimize the ammonia build up. The tank itself needs to be emptied but if you can keep the gravel moist some of your bacteria should survive the trip in the gravel.
At the other end, set up the tank and reload the filter with the media you had in the bucket. Pour the fish with both galloons of water into the tank and treat the rest as if you were doing a large partial water change. Fill with similar temperature dechlorinated water. Keep a close eye on your chemistry just in case you have lost too much bacteria but the tank should recover quickly.