Getting ready for winter in an RV requires some thought. Most of your plumbing will be exposed or semi-exposed to the cold and you run the risk of your plastic tubing freezing. Indoors might be a little more chilly than what you are used to, particularly the floor. Ours has thin gutters, slides, and roof vents that will need looked after.
The very first thing you need to take care of is your water hose. Your hose is hooked up from a faucet your RV park provides and goes to your RV. You need to ensure this hose does not freeze. They do make special hoses you can buy called heated drinking water hoses, but they are not cheap. We make do with a regular drinking water hose and insulate it. (You aren't supposed to use a garden hose, but we may have in a pinch for a couple of days. I don't remember.) Since we have a regular drinking water hose, we have to insulate it. Firstly buy heat tape. This isn't really "tape". It features a heating element and thermostat which warms the hose and keeps water flowing when plugged into a standard electrical outlet. Then we wrap some foam tubing around the whole thing. We also run the kitchen faucet full blast when the temperature drops below zero.
We have had instances of our water hose freezing before we bought heat tape. If it happens to you, unscrew your hose and bring the whole thing inside and throw it in the shower and let it defrost.
For the hook up that is outside, you can put a 100 watt light bulb attached to a 5-gallon bucket to ensure the hook up itself doesn't freeze.
Kind of like this, but attached to the bottom of the bucket, then turn the thing upside down over your faucet. Place a heavy rock on top so it doesn't blow over. Some RV parks have the faucet in a hole in the ground with a cover. We've never had a problem with freezing with this type and never used the bucket in these circumstances, I think because Daniel wraps the end of the heat tape around the faucet.
Just in case, it's always a good idea to keep a couple of buckets filled with water (and change these out every couple of days to prevent stagnation).
An RV air conditioner is located in the roof. We just pop the vent that is indoors and throw some regular pink insulation in there. With the vents that are in the roof, we bought these. They were on sale for $10 a piece. They would have normally been $20. Normally we didn't do anything though and didn't suffer overly much.
As I've said before we utilize space heaters. We actually only run the furnace to ensure the pipes won't freeze (not the water hose but the actual pipes) for in sub-zero temperatures, running the water may not be enough. We do have an electric fireplace that came with our fifth wheel, but a power surge took it out and we need to order a part from Canada before we can fix it. I've heard to leave cabinet doors open so heat can get to the pipes located in the walls, but ours are all located underneath. However, under the sinks can get cold and if I get paranoid I will open those doors.
At night, I've known people who swear by electric blankets, but we don't need to. (If you ask Daniel it is that I don't need to. I just leech his heat lol.)
If your pad is dirt, (and I'd advise against moving to where your pad is dirt), you might wanna park your wheels and jacks on wood planks to prevent sinking during the spring thaw.
If you don't have a completely covered undercarriage, I'd suggest some type of skirting. I wouldn't recommend square hay bales as these will attract critters. You can buy this skirting or just make it yourself using 2x4's and hard insulation (not pink).
Before winter sets in is a great time to clean your gutters and the tops of your slides of leaves. It's also a great time to re-calk any seams or whatnot you may have.
Here's a good link with founts of information. I may have forgotten something and all RV's are not created equal.
A lot of people winter in RV's. We've lived in two different RV parks during winter and both were full of neighbors who have always been extremely free with their knowledge. It is even a favorite topic among people living year round in RV's. Also, living in an RV has taught us to be imaginative and rely on each other more. I actually think we have a stronger relationship because of living in an RV, lol!