Any moble home company or contractor or if you are a do it yourself type of person can put the skirting around the RV. Just use some 2" insulation board as well are the outer cover material. Then heated dump hose and heated water connection. I would use electric heaters or if it has an electric fireplace as a primary and would get an extend a stay propane hookup for longer furnace run without a fill. Also thing like insulating the window area's while not looking all that good holds in a lot of heat. Another thing many use is a wave propane heater, the install and cost can mean the difference between comfort and cold. I stayed in a 5vr for a week in20 degree weather last year and was comfy. And it was not the quallity of the unit you have.