Hi
Spent several nights in Arkansas last December before wanting to move when it was freezing and now thinking about what we intend to do next winter. We were on a site which is unusual for us with full hook up.
1.At night we left on a fan heater on a low setting to keep inside above freezing. We do not like it hot at night!
2. Dumped the grey water in the evening so tank and lines empty. kept a few 5 litre bottles of fresh water to use.
3.Dumped the black tank in the evening and then left on line to flow. Urine should not freeze and flush down with a good lot of bottle water for fast flow out. In the morning check the dump valve is free and give the system a good flush. (you have a risk of small amount of ice on the valve sides stopping it moving/closing.
4.Disconnect the shore water and ensure the line is empty so it does not freeze!
5. We also fitted pipe wrap around the dump lines from the tanks and put insulation between the RV side and the grey tank - pushed up polystyrene packaging we had from a parcel which stayed there even driving.
6. Try and park your RV so the sun shines on it during the day and not under trees as you may in the summer for shade. This makes big difference during he day.
We had one morning problem - the day we were leaving! The black dump valve was stuck from ice on the insides and would not move. Used some cardboard to make a surround outside and put the fan heater there for an hour whilst we had breakfast.
This winter intend fitting trace heating to the lines after the tanks and putting a heater pad on the bottom, or trying to wrap around the tanks bottom the trace heating. Want to boon dock a lot so power will be a problem.
Oh one other thought is that some sites charge extra for a second electric plug in, so you want to be able to do it on you main supply and run your cable inside to your main panel. We were lucky in December we had an all in price for a month with electric at a great rate - 275 dollars! North of Mountain View at Sylamore Creek.