East to west Coast

I am at the other end of Idaho from Spokane. It is currently -15 as I write this. The roads are icy and lots of snow. They are more temperate up there than we are but it is bitter cold in the entire region through mid Jan. as it looks. I would certainly replace those tires that will come on the trailer with some LT tires. You may want to replace the ones that come on the pickup depending on what they are. Personally I would stay in hotels this time of year. Perhaps at min. I would leave the trailer in So. Cal. travel north to Spokane, do your business and grab your trailer on the way out.