First thing you want to have and be prepared to put them on are chains. You should do a test run with them on to make sure they don't damage the fenders. Road tires on MH's are terrible on winter roads. Most MH's are not built to withstand 0-15 degrees for any length of time. If you get caught in a storm your mind won't be on skiing....it will be on the MH and how your going to get it off the mountain. We carry our water with us and use it for flushing toilets and doing dishes along with water bottles for drinking. Even though you've tried to prevent your water system from freezing up, my thought is the chance of it happening is just not worth it. Also, instead of taking the MH up on the mountain, you might find a CG down below and take the toad up. Even then, we take our water with us because the likelyhood is the CG's have turned their water systems off. Besides when you get home you don't have to re-winterize your system. We know lots of folks who do this.
02 Fleetwood Discovery 37U, 330 Cat pulling a 2006 diesel Liberty..or..2011 4dr Wrangler..or..20' Lund Salmon/Halibut Hunter