Good idea.
Also keep in mind that all-season tires does not apply to the rockies. Get winter tires.
I cannot tell from your map where you are starting from and ending at....I wouldn't try to cross the Rockys during winter, but then I wasn't crazy about crossing them in the summer. Any food that doesn't readily freeze. beef jerky, dry cereal etc in case you get stuck for a couple of days...
Don't know if they have small heaters that can be plugged into cigarette lighters if you have one in your car...
Will you be taking small kids with you? No babies in case of getting stuck....avalances sometimes close the interstates, but they are the best to travel on as they try to keep them open before other roads... Good luck and get yourself on the freepers prayer list....