Extremely cold weather will challenge most any motorhome. General things to consider:
1. If you have already winterized your coach and need to travel into/through cold areas, leave it winterized and use jugs of water for drinking, cooking, flushing your toilet.
2. When you get to warmer areas, filled our fresh water tank and enjoy.
3. If you have not winterized and need to travel into/through cold areas, keep your heat source on. Most class A's will do fine if you keep the heat on for comfort inside the coach. The most vulnerable freeze prone thing is your fresh water pump since most (including Winnebago) mount the pump on/near the floor of a compartment and the floor is generally not insulated. In these cases you may need to use something in that compartment to prevent freezing...a trouble light or a small electric heater.
4. Very cold weather will test your batteries and other systems. Make sure everything is in top shape.