Hi rosalie - I can totally understand your dilemma but have to say that we have driven through France four or five times now and I am getting to really enjoy the journey (500 miles down from Calais) (am not a good car traveller myself). All I would say is that I have yet to find a decent service station so pack a cool box full of sarnies/wine/nibbles - particularly if your OH is one to put his foot down and drive straight through (my OH likes to do that too). By the motorways there are several picnic areas which benches/tables and toilets and actually quite pleasant as they are just off the main roads (have spent many a snooze in the sun at these picnic spots).
Anyway thats my advice - also backing up merc1's advice re some good CDs too. I also read a book although I know some people cannot read whilst in a car (it would make my OH sick).