Can you identify the route I took from Avignon to Turin in 2015?

In 2015 I found myself in Avignon, France having just been mugged, all alone, with no money, credit cards etc. I had to make it to Italy and didn't have money to use toll roads. My navigator (long defunct) was able to find a route to Turin which I followed almost without a pause (as I had a ferry to catch on the Adriatic coast). I would like now to take the same route once again to revive the memories of this incredible (for my otherwise mundane life) adventure but being a native of neither France nor Italy I would need some help to identify the places. What I remember is the following:

• After Avignon my navigator took me through the most breathtaking alpine scenery driving on a simple two lane road through narrow gorges with streams of pristine water everywhere.
• I then came to a village / town (I would say in the order of 2 - 3 thousand inhabitants) up in the mountains approximately 90 kilometers from the Italian border. The town had a railway station and a gendarmerie.
• After a short pause for sleep in my car, I drove on and a short way from the border (10 kilometers) I drove through a spectacular town on the mountainside with a very impressive fort on its highest point.
• Then came more ascent through hairpin bends and finally, at what surely was a saddle point on the mountainous landscape, came the border which had a very modest border control post. What was very characteristic is that there was a ski center right on the border straddling both countries. I could see people with their ski gear on ski lifts just a few dozen meters off the road.
• After the border crossing it was literally descent all the way to Turin.

Can you help me identify the border crossing and the major places I went through?