Hi Peter,
We have used a different route. However, I don't have a map with me, so this is just the general drift...
Motorway from Calais to Troyes. From there, strike across country (N77, I think) to Auxerre and from there towards Nevers & Moulins. You can then pick up the motorway just to the north of CF.
We've used this route travelling in both directions and, depending on sailing times, have usually stopped overnight around Auxerre or at the municipal at Troyes.
Jo