How wonderful for Patches and Ginger to have you on their side. When you move them to the new place is their any type of out building (garage, shed....etc.) that they could live in so that they can get used to this area as being their new home. I fear they might just wander off if their was nothing keeping them there. Think about how scarey it is when one of us brings home a new cat and it does not know how to act in it's new INDOOR environment. The outdoors must be even more scarey than that.
Best of luck to you with both Ginger's vet visit and the move.