This is the best route and least likely to be treacherous. While the hill on route 4 in killington can be scary, it is an interstate highway, well traveled and gets plowed frequently. Can't say the same for 125 or 73. I think in normal conditions, navigation (waze or google maps) will tell you the fastest route is 73 brandon gap, but I've tried it multiple times and never found the time saving to be significant.
Thanks for this helpful info!