Hello again Scottishlass, I agree with petercoachman on the route, have a look at the viamichelin site, it will give you the best route, probably as suggested. I have used this route and found traffic quite light.
You also ask for stopovers, to be honest we never prebook overnights as quite often factors will cut in to affect traffic flow, ferry is delayed etc and you cannot guarantee where you will be at a specific time. What we do is when we feel ready to stop is pull off the autoroute and ask the booth operator in a mixture of broken English and French, or travel to the nearest town. We have never had a problem yet, we have always found a site, some excellent, some not so good but have coped for one night, they are always signed. Good luck.