Route to Croatia

Hi there.  We are booked on the Dover Calais ferry (through the Club of course - bargain deal).  Then it is off to Crotia.  Anyone got any routes?  Advice? etc.  You can assume I know nothing (but of course that can't be true - can it?).

I love France and would like to take a route through Eastern France - but if other routes are better I will maybe be persuaded...

I look forward to a lively and informative discussion.