We travel mostly in the Winter to get away from the crowds here in Florida and to experience the National Parks without the crowds. The Grand Canyon in January is beautiful and you have the park mostly to yourself. We were one of six RV's in the entire RV park inside the Grand Canyon. The same goes for Yellowstone in November. We very seldom use our propane furnace alto it does do great to take the chill off in the morning. We keep our fresh water tank topped off and never hook up to RV services unless it is to dump our waste tanks and top off the fresh water again. If the weather is going to be below freezing, we place a 100 watt incandescent light in the wet bay which has kept things from freezing down to a little below zero. Our wet bay is covered with spray foam insulation and when closed, the light bulb does well to keep the temp above freezing.
We use our roof top heat pump and a portable heat pump to warm the coach, as well as an electric ceramic heater. In addition, we use a low voltage electric blanket at night. Neither my wife nor I have to have the coach at 80 degrees so keeping it at 65 is very comfortable for us and our mountain dog. My roof top heat pump usually quits working at around 30 degrees but our portable heat pump will work no matter what the outside temps are.
During the Winter, in snow country, most roads are kept clear altho after a heavy snowfall, it may take a day or two to clear off some of the secondary roads. We have never had trouble finding roads to drive on but I do carry snow chains that I have used to get in to and out of some RV parks that do not have snow removal equipment. There are some places in the mountain highways that require you to have snow chains for RV's and you can rent them at a lot of locations. For me it was easier to purchase them which gave me time to practice installing them in Florida before we got in to the snow. Now it takes me about 20 minutes to fit the chains.
I use pads under my leveling jacks to prevent them from sticking to the ground when temps get below freezing. I have no problem retracting the jacks but sometimes it can be a challenge to pull the pads out.
I have driven across I-80 in Wyoming during a blizzard and the only problem I had was that my windshield defrosters had a difficult time keeping the ice melted at the top of the glass. It would eventually melt and slide down the windshield but the roads stayed clear enough so that we had no problem.
Obviously the world does not come to a halt during the Winter. There are plenty of other motorists on the roads and about the same amount of trucks no matter what the weather is like. Not all RV parks are open in the Winter so it is a good idea to check to make sure that you will have a place to stay. If you do not mind Walmart, or a truck stop, there are always places to park. We have always been able to find an RV park somewhere that is open.
Winter travel is not for everyone. It takes a little extra effort on your part and it takes a willingness to want to explore some beautiful ares of the country during conditions that keeps most people inside. For us it is worth all of the hassles and thanks to satellite TV and the internet, we have never been caught in a storm where we would be stuck for more than a day.
We also have a curtain behind the front seats which we close to keep the front of the coach comfortable when driving in zero temps. This allows our dash heat to keep us comfortable.
To answer your last question, we always tow a Chevrolet HHR with our gas coach and have had no problems in the Winter in the Western mountains.