Hi,
Well, we must be mad then because it was blow zero (F) for the first trip in our trailer....and we had a great time.
In November, the valley is not likely to be too cold (I used to climb there...yes, in the winter) and if it is, get rid of the rig. That said, there are many things you can do to increase your comfort level and how well the rig does. Start by reading though this and other forums about winter camping (note that most threads are for camping in temps well below what you are likely to experience). Probably the only real issue you will have is keeping the batteries charged (because the furnace uses so much power). You can either use a different source of heat or figure out some other method of charging (generator is one method). Be wary of propane space heaters (some love them, some hate them) until you fully understand what you are getting and any possible risks they may pose. Also, reducing your power consumption, by changing to LED lights, will help quite a bit.
Most importantly, "have fun and enjoy yourselves"