I completely understand about the cats! We travel with 3 also. Definitely make sure to have scratching posts along.
If the cg is open & you're able to stay the night - then perhaps their facilities - bathrooms, laundry, etc will also be available. Then you could easily travel with just jugs of water for drinking & brushing teeth. You just lose the convenience of your on board toilet until you're able to put water in the fresh water tank.
With RV antifreeze in your black & gray tank they should be fine - you'll just have no fresh water in that tank.
Make sure your final destination has space for you! Arizona seems to be full in the winter!
Safe travels to you & your sweet felines.
