One of the best resources of the RVer is propane. Its use should not be underestimated.
Most people probably consider using propane in an RV for cooking on the stove, and that undoubtedly is its main and most constant use. And when you use propane only for cooking, a 5 gallon tank can last a long, long time.
But there are other uses of propane as well.
Our heating system works with propane. The furnace blower is electric, but propane is the resource that creates the heat. Using propane to heat our trailer really does consume that fuel, though, so we use it sparingly. When the temperatures are not too cool, say dipping down to the mid-50s or so, we simply use a space heater to warm the trailer. Once the temp dips below 50 or 55, though, we start using the furnace. We have an electric heater in our bed, so we don't turn the furnace on very high at night. Usually, I'm the first to awaken in the morning. When I do, I flip on the furnace to about 70 degrees, then hop back in bed while it heats the trailer. After the trailer gets comfortable, I get up, turn off the furnace, then flip on the space heater to keep things comfortable. Again, using propane to heat a trailer consumes a lot of propane very fast.
Our refrigerator is a two-way. This means it will run off 2 energy sources. When we are in a park with hookups, we run the fridge off "shore power", which is the electrical power provided by the park. However, when we are in transit, we switch the fridge to propane, which operates with the trailer battery. The drain from the battery is slight. In fact, when we used to just take week long trips from home, we would turn the fridge on using propane the day before our trip. By the time we were ready to leave the next morning, the fridge would be cold and ready for stocking of cold items. If you run your fridge on propane while traveling, you must turn it off when you pull in to a gas station. Since you are running propane, there is a live flame there. Yeah, this is a bit of a hassle, but a necessary one.
Propane can also be used to power the water heater. I never use propane for this, though, for we always stay at parks with utilities. I'd rather use the park's electricity than my propane because I'm a cheapskate. Some people will run both propane and electric at the same time to heat their water. These folks usually have large families, and they claim the water heats faster this way. We've never had a problem with hot water, though. Donna usually showers first in the evening. By the time she is done and I step in, we always seem to have enough hot water.
We also have a grill that attaches to the outside of our trailer and connects to the propane system. This has come in handy so often during drought times. Many counties have not only burn bans, but bans against charcoal fires. The only grilling they will allow is with gas grills. At first, I didn't like the way the grill cooked, but over time, we've adjusted to it and learned how it heats, and now we are quite happy with its results.
As I write this, it is September 22, 2012. The last time I purchased propane was April 11, 2012. My 5 gallon tank was empty, and it cost me $17.96 to fill. Since then, we have spent at least 70 nights in our trailer, and we are still using that tank of propane. Of course, most of this time was during warm weather. The nights are beginning to cool now, and we are using the propane to heat our trailer, so it will soon be time to refill the tank. I have 2 tanks and I monitor their levels closely. When one is getting close to empty, I turn the other one on. When one does go empty, the system will automatically begin using the other tank.