I keep the case on a flat moving dolly I got from Lowes or Home Depot. The dolly was left over after a couple of moves. To lift the case in and out of the car I used some retired lengths of climbing rope. The rope is attached under the handles with some velcro strips. The velcro take no load and makes it very easy to remove the rope if needed.  The rope also serves as a tow line when pulling the case from storage to the garage. A simple solution with available materials.