"Cold camping" can be done in an RV but it is anything but comfortable. RV's are not insulated very well, resulting in enormous amounts of propane being used. Probably on the order of 20 gallons every 24 hours. Getting propane that often will be a chore.
I camped for 3 days in -10 degrees in Mammoth. While it was Ok for the short period, I could not imagine what 8 weeks would be like. Everything freezes, inside of your windows (condensation), exterior water supplies, power cords get brittle. If you have never driven with chains on an RV, well, let me tell you, it is no picnic. Some of the passes into Colorado get into some serious elevations +8,000'.
I respect your ambition, but I think for the inexperienced RV'er, you are going to be miserable. I was a seasoned RV'er and it was barely tolerable.