Some great tips from the community in an article posted by
@Corrie on this
post. I'll preach again though, wear merino wool because it's natural properties are amazing. Also, keep the air around you warm and it will keep you nice and cozy.
As far as rig related stuff goes, I'll state the obvious. Make sure your tires are M+S or have the snowflake symbol if you're driving in winter conditions. Most of all don't get complacent, just because you have 4 wheel drive doesn't mean you are invincible.