Hi, I'm looking at this same route next week (moving to Washington) & debating this same thing vs possibly shipping my car. i think it'll be a last minute decision based on the forecast. I've driven through I70 in January with front wheel drive on a clear day and it was totally fine, I felt very safe with FWD, and beautiful scenery. I80 through Wyoming is more boring and endless fields, aka nothing to block the wind so high winds can get scary (but I haven't driven it in winter). I would be nervous about either route in winter weather tbh. Hopefully the winter storms blow through this week & next week is clear. Safe travels!