You'd need to empty the tank completely each time. For travel, put the gravel, decor, and filter into one 5 gallon rubbermaid container (keep all of it covered with water) and the fish into a separate 5 gallon rubbermaid container. Try to keep at least 50% of the tank water and do not rinse anything (gravel included) or you risk the tank go through a major cycle. Keep both containers out of extreme temperature. If you have a lot of fish, you might consider a battery operated air pump and air stone for the trip. You probably want to stay away from live plants - plants don't like to be disturbed. Stick with hardy fish as well as unless both locations use the same tap water source, you'll have the fish needing to acclimate to the water each time the tank is set up - sensitive fish won't do well.