I did Sault this September on compact, 50/36 x 12-27, midway through a trip through Provence and some of the Southern Alps including Col de Bonnet-Restaufond.
We'd done 45-50 miles that morning from the previous night's hotel to Sault, started the ascent after lunch at about 2pm
I found it a bit daunting initially, down into my bottom gear of 36x27 on the bit past the chapel and thinking to myself it was already a bit tough and it was a long way to go, but then as it gets higher it levels off a lot and becomes a lot easier as it climbs through the trees.
But then past Chalet Reynard it got tougher....
Unlike Fab Foodie's ride up, my day was freezing and windy : very windy indeed - on some of the switchbacks I was crawling, barely able to penetrate into the wind, then I'd go round the bend and practically be blown up at 12-15mph, then round the next bend and crawling again.
Eventually I got to the top, tried to sprint the last 50m out of the saddle and was blown sideways clean off the road.
The top was intermittently in-and-out of cloud and it was 6 degrees C - but with windchill it would be easily below zero.
I got cold looking at the views and taking a few photos, went into the shop for a warm-up, bought a shirt as a souvenir - the woman in the shop was giving-out newspaper to stuff up your shirt as insulation.
Came out, some others in the group had now arrived, few more photos - but now I'm bitterly cold.
I'm wearing a short-sleeve shirt, the new shirt and a waterproof jacket, but just bibshorts and short-finger gloves : my hands are frozen.
I tried to cycle down and it was terrifying, I'd be doing 5mph into the wind but on rounding the corner I'd be blown to 30 and beyond except that gusts were either trying to blow me off the mountain or into the path of cars coming-up, and I was so cold I was shivering and my arms had locked-up so I was swerving about all over the road and my fingers weren't able to brake smoothly.
It took me a white-knuckled 20 minutes to crab down to Chalet Reynard, passing a few people who were even walking their bikes down. Other people going up were turning back. The wind was getting worse and the ones at the back of our group didn't make it up.
After a coffee and a warm-up at Chalet Reynard it was fine going back down to Sault, but I still didn't dare go above 35 or so because the road's a bit rutted and even though now protected by trees there were still gusts every time there was a gap in the treeline.
As others have said, you drop down to the river just before Sault and then have to climb perhaps half a mile or so up into town, which is a bit of a sting in the tail.
So for FF it was brutally hot, for me it was bitterly cold and windy.
On a good day it would be easy enough if you're fit and determined, on a bad day it's tough, if a very bad day when it's a gale and snow at the top I'd not bother.