If your traveling or living in the MH, and the call is for overnight frost warnings, your probably OK as long as there is heat inside the MH.
Frost is generally caused by the earth radiating its heat skyward. If there is something above the ground to reflect/re-radiate the heat, i.e. clouds, bottom of MH, etc., you don't get frost because the heat radiated by the ground is reflected or re-radiated back to the ground.
A temperature excursion of a couple degrees below freezing for a couple hours should be OK.
If you have a City water connection and hose, you may want to turn it off and remove the hose as a preventative measure.
2001 Coachmen Mirada (Ford F53 6.8L V10) - Toad 2003 Saturn Vue
It won't do MACH 2, but I can get a sandwich and take a pee.