Will water lines freeze?

We will be heading to Utah (from Minnesota) for a week and Are trying to decide whether we fill our tanks before we go.
The overnight temps for the first 2 nights are forecast to be in the low 20s. After that, it should be above freezing.
I’d we fill our tank, will our lines freeze overnight if the inside of the camper is heated to 65 degrees and it warms up during the day?