Dare I travel with water in these temps?

the 38 gallons of LP, should be way more than enough for the trip
your moving (thats water agitation) and the furnace to stay warm
i would expect no problems with freezing

There is some serious cold weather to the west of you heading east, plus if you have a Facebook account you might like to watch this video of Louisville taken by a professional storm tracker 20 hours ago

Kentucky storm clicky.

As far as your post is concern between the furnace and sloshing of the water tank I think you would be just fine. Not to be a doom and gloom type, but maybe having a full tank of water, propane and food on board might come in handy with this weather that is in front of you.

Safety first, Ro. Keep it winterized until you get south.

I forgot to mention that we are leaving tomorrow morning. I guess I'll pick up some more RV antifreeze and a few jugs of water and be safe.
Thanks very much for your input.

Travel with water, in jugs, until you're free of the punishing weather.

Flush the potty with red RV antifreeze as needed.

When are you leaving?

We have one day with a high of 14, low of 9, forecast next week for TN. It will be colder in Lexington and probably about 10 degrees warmer in Atlanta.

Check the forecasts and if possible avoid the very coldest weather.

I don't know how well your tanks are insulated, but at highway speeds, that furnace heat isn't going to very effective. Every gap will let in cold air.

In your shoes I would consider leaving the RV winterized until you hit temps at least in the mid-20s.