Chowder -
There is an entire forum on cold weather camping. Unfortunately, you have allowed your membership expire, so you do not have access to it. I will leave your question here for a few days so you can see the immediate responses, but you might consider renewing your Sponsorship. Go to the front door of the forum (
www.trailmanorowners.com) and click on the Site Sponsorship link.
Since you will have shore power available, you should take a hair dryer with you. It is the world's most useful tool for thawing things (like drain valves) that are frozen.
You might also consider taking water in several gallon jugs or 7-gallon plastic totes in the bed of your F-150.
If you start with warm water, either in jugs or in your fresh water tank, you should not have trouble while you travel. It takes a long time to freeze a big block of water, and 20 degrees is not especially cold. Think of how long it takes to freeze a tray of ice in your home freezer at 0 degrees.
Bill