Driving at night is best case scenario. way less traffic. They do a great job of keeping the roads clear. The only reason why you wouldn't want to go is if it is blizzard conditions. Make sure you check the weather for loveland pass, because the weather may not be bad at denver airport, and still be a blizzard up there. They can also very quickly put a chain law in effect in that case so watch for that as well. How long it takes depends on where you are going. If your just going to the Dillon area. your looking at 1.5-2 hrs from airport. Breck and copper add 15 minutes, vail add 30-40. Big heads up if your travel plans have you leaving on a sunday. The drive down on sundays are the worst, it will take you 2-4 hours to get to airport so plan accordingly.