Thanks for the suggestions, by the time I was able to spend time on the problem the warmth of the sun, (27 deg!), solved the problem for me. I had to thaw out the black and grey tanks, but I did that with a space heater and running hot water down the grey tank and letting it mingle with the black. It worked and we're back on track. We are working in a campground called Enota in a town called Hiawassee. Their website is www.enota.com
and they are always looking for workampers/volunteers. If you wanted to come for a few days and were willing to do some labor you could likely get free camping/meals.
We currently have about 4" of snow and are located just down the hill from Brasstown Bald, so the elevation keeps us cold. It has gone down as low as 5 degrees since we've been here and we have been very comfortable inside, while my neighbors in the traditional breadbox trailers have been freezing. I found an Airstream only park about 5 miles from here, with a 345 motohome in residence and a ton of older trailers being stored.
We are going to so. florida from here in about 6 weeks, so I'll be posting to ask for advice about the awning, which is supposed to have some problems.