No worries at all. Temperatures must be below freezing to change from a liquid to solid state. I have regularly camped with temps down to -5°C (and even a bit lower a few times). As long as daytime temps get a ways above freezing, you will be fine. Other than the holding tank, and the water line to inside from it, all other fresh water is inside your trailer.
The only problem I ever had was on the last camping trip on year, I went to winterize before I tore down camp, and the low-point drain had frozen up a bit. I just held it in my warm hands for a while, and away it went.
2017 Escape 5.0 TA (someday soon, I hope
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
“Most folks are about as happy as they make up their minds to be.” — Abraham Lincoln