We have camped with the lows in the low 20's at night with the daytime highs in the range your talking with no issues. I do crack open the cabinet doors that have plumbing in them to just allow a little extra heat back to them. I would put water in the FW tank for night use, and fully disconnect the hose. I would not want the plastic hose fitting to break.
With a 5ver, you should have a heated underbelly, so the tanks and any water lines should be fine.
This morning our low was about 20 degrees, and the temps have been very cool for the past few days. I checked my small garden pond and it had about a 1/16th of an inch of ice floating on it. So if you do not have a heated underbelly your tanks will have no issues.
In our HTT, I put an electric mattress pad on the bed this time of year, and it makes it so much more comfortable!