Two primary routes, as Independence Pass is closed in the winter. Here are the options thanks to google (and my red X):
If you are driving in the daylight, the weather is good, and it hasn't snowed for a while, the most direct route over McClure Pass has absolutely gorgeous scenery. I love that drive in a car that likes twisty roads. Otherwise, head up to I-70 for much faster, straighter and less likely snow-covered Interstate and four-lane highway.