Re: Ok heres a question for the experienced campers.
Peter and Liane,
It's no contest. Skirting will help a lot, but when temps drop far enough, it won't protect your tanks and water lines from freezing. You have to have tank heaters and if you want running water, you'll need heat tape. You'll also need to decide if you want to run off your fresh tank, filling as needed and putting the hose away, or using a heated water hose. Also, your gate valves may freeze. If they're easily accessed, you can probably thaw them with a hair dryer when you need to operate them. Otherwise, you should consider valve heaters.
Plan on running a heat lamp over the water pump/plumbing area and if you have a Universal Docking Center (UDC), hang a drop light there to keep the water connection from freezing.
Plan on running the furnace a lot. You'll also want to have at least 1 ceramic disc heater for additional heat.
If the park allows it, you may be able to construct inexpensive skirting out of wood or other building material.