I agree there is no way you are going to do it driving 8 hours a day with only one stop. We went at the end of August and avoided all motorway tolls: My journey details were as follows:
29 August 2010 Arrived in France via Eurotunnel left train at 08.10 arrived south of Bordeaux at 19.00 hours having driven 582 miles.
30 August 2010 left Bordeaux at 06.45 and arrived Playa Flamenca at 19.15 having driven 676 miles. On the second day we went over the Pyrenees.
Both days we stopped for 3 x 30 minute breaks. Our avarage speed for the time we spent driving was around 61 mph. However, there were considerable amounts of time spent going at 90 to 100 mph. Between Calais and Playa Flamenca we were only passed twice. I think if you go on the pay motorways you might be able to improve your average speed although it is further and will cost you a lot in tolls, from what I could discover.
We stayed at the Premiere Classe Hotel. Room only cost was 45 Euros, we did not have breakfast there.
You may be better off catching a boat to Santander or Bilbao and driving from there. We are trying that in March.
This message was last edited by kev2006n on 01/12/2010.