We used to use our antique coach in temperatures below freezing all the time, not just down to little numbers, but some had a dash in front.....
What it really all comes down to is simple.
Is this unit built as a 4 season?
Can you warm the trailer up now?
If yes to the above, warm it up, put water on and clear the system taking as much of the red stuff out in buckets as you can. (Someone that came by asked what I had killed on the lawn.)
As to putting water on, set up the dry hose, fill the potable tank, disconnect and walk the hose empty and take into the warm before you have 50' of rigid hose to manage. If you disconnect both ends and walk and coil, this it not that hard to do.
If it is not a 4 season, buy a case of bottled water and drive south. But not today. Wait until this storm has passed.
Matt