Jon,
     I have made the journey lots of times, if you go motorway its fast but not cheap, from Calais to Tortosa one and a half to two days depending how fast you want to go and thats through Paris with a satnav.You can avoid Paris and go via Rheims which adds something like fifty miles to the run. Also you can take the Route National roads but be prepared for long hold-ups and convoys which you can't overtake easily if you have right hand drive,obviously this way takes longer but is more reasonable.Try and refuel off the Autoroutes if possible,much cheaper!
As for stopovers I favour the Logis de France because they are family owned small hotels and normally the food is very good. There is a catalogue which can be obtained from the French Tourist Office or if you find a Logis they have this free of charge on the counter. There are motels and hotel groups all the way down the autoroutes at all prices,Campanille,Ibis etc.........all can be found on the net as can Logis de France.
Hope this helps a bit.................any questions, come back!

                                                    Old Nelson.

I have done it a number of times and prefer to go via Lyon not Paris, as old nelson says, it is slow and easy to get lost, the peripherique exits are not well advertised and IMO, it is really easy to take a lot longer timewise despite saving 50 odd miles. I usually drive it in one go, via Lyon on the Autorutes @90mph it takes 13 hrs +/- from Calais.

If you want to stop, in the S of France, Carcasonne is worth a visit, only a short hop off the AP7-E15 coastal motorway [A61-E80 to Tolouse] .. and it has a Formula1 hotel nearby.

Thank you all for your advice we are looking forward to the journey it should be quite pleasant
as we plan to take a couple of days and travel through the night
thanks jon