There is no reason whatever that you can't stay in your rig for the trip down. We leave Michigan in freezing weather, and arrive at our first night stop still in freezing weather. We use a combination of electric space heater and the on-board furnace for heat, and we take three gallons of water for drinking and making coffee. Most places have the water at the sites turned off, but the electricity is on, so we flush the toilet with pink anti-freeze from a couple jugs that we keep in the bathroom, and use the campground washroom for our showers in the morning. If the washrooms are closed for the winter, we spend the morning on the road THINKING about a shower, but settling for just a quick wash up in the sink, adding more anti-freeze after draining the water in the sink. This only happened to us once, however. Most parks have the showers on all winter......at least once you get a bit further south. By the second night, we usually find the daytime temps in the 40's or 50's, so even if the temps drop below freezing at night, the tanks won't freeze hard enough to cause damage. To protect the more fragile water lines, we leave the cabinets open so that warm air from the heater and/or furnace can get in there to keep them from freezing. We also don't use the park water hookup unless it's going to stay above freezing, or we use it while it's light, but disconnect at bedtime. By the third night, if not sooner, we can completely de-winterize and go back to a normal routine.
By the way, regarding food, we take along a lot of stuff that we can just pop into the microwave, such as Hormel Compleats dinners, pot pies, etc. For breakfast we use the toaster for waffles, toaster strudels, and the like. We also take along a dozen hard boiled eggs. Sandwiches and chips suffice for lunch. You don't even need to use your fridge if you plan your meals around non-perishable foods, or use a cooler for the first day or so.
