We have a place near Frejus and drive down 2-3 times per year. When the kids were smaller we used to stop over but now do the run overnight in one hit (more time in the sun).
Things we've learned over the years:
* During holiday time, travel mid-week as the roads are quieter
* Be aware though that the majority of traffic overnight seems to be large trucks, but they do behave themselves quite well
* Don't be tempted to shift into hyperdrive - we now cruise between 70 and 80 - as the police are clamping down on speeding big time (especially during holiday time)
* Definitely get the tag from saneftolling.co.uk - you pay a returnable deposit, and €6 for the months you use the tag, but it saves so much time at the toll booths (day time peak travel has meant that we have saved over 2 hours compared to friends travelling down without one) plus it's always good to get one over the locals who smirk at you when they think you're in the wrong lane

* If stopping for lunch / dinner, try to avoid the local time for doing so. For example, if going during the day we stop for a late breakfast / early lunch at about 11:00. The French, as creatures of habit, will tend to dive in between 12:00 and 14:00. Upshot is that the restaurant is quieter, and then you gt out and enjoy a couple of hours of quiet road.
We're doing a swap with some friends who have a place near Perpignan this year - not explored around that part of the world very much so looking forward to it. Supposed to be a little quieter that the usual Cote d'Azur area, and the Med is warmer than the Atlantic - mileage-wise it works out about the same (just over 700 from Calais).
When you decide where you're going, drop a line to the local tourist office and they'll be happy to send you loads of stuff to help plan a great holiday.