I haven't been to the Park in a long time, so I can't be of much photographic help. I do know that when they close the road, they close it. Even snowmobile access is restricted to official tours. That means you either ski in or poach with a snowmobile.
I don't find fall to be terribly attractive in Montana. Everything is dead and smoky and you don't have exciting summer storms or the peaceful blanket of snow that winter brings. Of course, there are always photo opportunities, but fall isn't my favorite. Yellowstone might be considerably better than here, too.
If you go to the Desert, I recommend a stop over in Zion. It's really beautiful in November. It's mostly on the way, too.