we used to do the Denver/Bay area run a lot when we lived in golden, CO. You can figure about 24 hours for I-70/80. When doing it solo, you could do Denver/slc in one day, and then slc to the bay was a long haul. 3 days would be no problme. Winter can be a real *****, tho: between plains blizzards and ice fog in the slc basin, you never know what you'll get.