so far as water in the water tank and lines on a VW camper?  For winter, I normally just drain them, and for winter camping, use jugs for water, which I protect as much as I can.  Someone on here inquiring about heat mentioned that the water lines froze at 22 F.  I've normally drained everything as soon as I expect any temperatures in the high twenties.  My van is in the driveway right now, kitchen water tank empty.

Thanks much, David