Kellie - if we get enough of a freeze to worry about it - I'll disconnect the hose and use water from my tank. It won't get cold enough and stay cold enough to worry about the water in my tank. Most likely, I'd only have to disconnect the hose overnight - but would keep it disconnected on days/nights working, just to be safe. Otherwise, I could get heat tape for the hose.
Nothing else is in danger. As long as I'm heating the rig, pipes won't freeze. You have to do that when it's sitting unused, not heating it.
If you had any other questions I didn't answer, ask away
I actually doubt it'll ever get as cold as it did at Kaibab the last month I was there. And I've been in cold in the mountains, etc.