Here is a wild idea -- if you are coming from Washington, cut over from the 5 in Northern Oregon to 26 to 97, down through Klamath Falls, and then to Alturas and south on 395! We prefer this to 5 through the Siskyous and the Central Valley of California -- much flatter, better scenery, less traffic, much better road surface (smooth asphalt, instead of a bumpy concrete freeway). Plus you get to see the Eastern Sierra.
Having said that, I have never taken that route in really snowy weather while towing, so I am not sure it is safe. I have towed on that route several times, with no problems. And I have driven it without towing in the winter.