I've not done this in March, but in thinking this through, I think it depends on your plans to camp or not on the way home and how cold the temps get as you go further north.
Assuming you are going to camp on the way home and its freezing, I think the only thing to worry about is freezing the lines as you drive north.
Drain and blow out the lines or use AF. Blowing out the lines is probably easier. Then I would use bottled water for cooking and campground showers and bathroom.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD