Freak deal if you get snow in October. I'd be more worried about getting 2 flat tires at the same time.
We ride Moab in October, and sweat during the day. We ran a space heater in a tent trailer two years ago, nothing last year.
I-70 from Sevier to Kanab is a good road. It has its share of twists and rollers, but do not hesitate to take this route. You aren't going to miss anything if you don't continue to I-15 and then head south.
I grew up in Page. Personally, if you aren't going to go to the North Rim of the Grand Canyon, just take the route through Page. There is no need to do the climb just so you can turn at Jacob Lake and head down the switchbacks with a big trailer; that would just be a waste of time and fuel. Besides, the 89A from House Rock Valley Rd to the river is shoulder-less and not the smoothest stretch of pavement. In a car/truck/bike sure, great alternate with some good views, but not running heavy.