how often do you drive that?
i leave every saturday morning for keystone and it takes me about and hour and a half to 2 hours.
traffic usually isnt bad at all.
like two weeks ago, whenever the last time the city got snow and summit didnt, it took me about 2 and half, because there were three plows i couldnt pass for 10 miles before the loveland pass exit.
op you might see more traffic 1 since you are leaving later, 2 since the texans will be invading around this time. but it will no where near take 4 hours.
the worst time is sunday after noons, there are a ton of trucks which slow things down in the central city area, that is where it is the steepest and sharpest turns.
not to bad once you get used to it though.
i would rent a car with 4 wheel no doubt, even though it doesnt look like snow you never really know.