I've ridden the roads around Nice. Beautiful but apt to be a bit hilly. I've been to that part of the world a few times and I'm hoping to take my wife (who posts here and talked me into joining the forum) there on bikes. Someday.

Couple of ideas. Don't "plan" on doing so much distance per day. Touring is about enjoying the trip (and eating). I've done 120 mile days over mountain passes with a full load and I've spent a days where I've been lucky to hit 40 miles. Each trip will (or should) develop its own rhythm.

If you need to plan for things like accommodations, best to experiment. Load yourself up with roughly the amount of gear you'll take, then toss in another 10 kilos for good measure and do a ride at a nice pace. You should be a little tired at the end of the day, but not totally knackered. Plan based on that. If I had to pick a number, I'd say 60-70 km per day would be a good starting point.