Then theirs idiots like me that went into the mountains and used my TT as a ski hit! 0-15F night vs day at times.
Reality, do what you doing. I never turned the heater off, kept it around 70f. Then again, you do not appear to have 4 kids from 6 months-18yrs with you over the 10+ yrs I did this.
If you do this alot, find the manual drain lines in the main lines, remove them! Water will freeze up, and you will not have water beyond that point. For me it was bathroom and hot water heater at rear of trailer. The front kitchen had water.
If you have exposed gray and black tanks, the may freeze, if temps are lower than freezing for a few days. They usually have room to expand, not a big deal.
I found having door vent covers to be a good thing when it snowed. Even with 2-3' of snow on the roof, we had ventilation. With out we had none.
My 02
Marty