Ha! My parents are from Blairgowrie, so I've been through there often, but never to ski. Beautiful area any time of year. Apparently the Glen Shee road used to be a lot narrower, steeper, and twistier, and they sometimes had to reverse up one of the grades (reverse gear was lower than 1st in Dad's first car, a Hillman Imp, IIRC).
The twisty bit was called the Devil's Elbow [1], I remember going over it as a child before the modern road bypassed it. My parent's first car was a Hillman Imp too, I used to sleep on the shelf over the rear engine for part of trips up to Aberdeen.
I have had to fit chains to my car to get over the Cairnwell Pass, nothing passed me while I was fitting them and I could see people turning around lower down the hill, didn't see any gritters.