Hello and welcome to the RTA forums !

I am afraid there is no way to predict what the weather maybe over Christmas across the entire country and nowhere is immune from winter storms, so at the moment it would be a case of wait and see.

I80 looks to be the most direct route and the less time you are on the road the less chance of seeing a storm, but I would leave your options open and see what route is most viable when you have a weather forecast a couple of days or so before you travel.

Expect your journey to be 5 to 6 day's with 10 hours of travel per day.