They usually have a mostly fibrous root system, though old vines may have a few hefty roots going deep. Fortunately, they are pretty forgiving about root disturbance, as long as you prune them back hard just before digging them up. I would wait until deeper in the fall to move it, unless you are in the northern part of the State, where it is better to wait until spring. Be sure to have the planting hole ready be fore you dig it up, since they don't like to be out of the ground long. I would also use a good root stimulator like Superthrive.