We are off to Spain (Bonterra Park, Benicassim) at the end of December, although we are going from Portsmouth to Caen and arriving at 9.30pm. Our first stop is at Des Capucinnes just over Pegasus Bridge, the next say we go to Poitiers, Le Futuriste. From there we go to Larrouleta at Urrugne and then on to either Zaragoza or Camping Altimiro in Spain. All these sites are either ACSI or Camping Cheques. Going from Calais you will most probably need a stop between Calais and Poitiers as I have never been that way.
Depending on your dates you could go down the A26 you could make camping de Troyes your first nights stop. If you wanted to use the A16 then the A 28 your first night could be at L'Escale which is 25 minutes from the tunnel. Both sites close on the 15th October.