First time abroad with nippers!

Hi all, we are going to Les Raguenes Plage in Brittany for our summer holiday.  I have planned it quite well due to having two children under 5.  We are travelling from Dover to Calais then onward to  the Le Brevedent site in Normandy for a stop off then doing the same in reverse on the way home after 12 nights in Brittany.

Does anyone have any tips for these areas? I've planned our route on paper and we will have sat nav and a map.  

We are staying at the black horse site both ways also as we are from the Peak District so quite a trek on this side of the journey to!

Here is the stop off site...

http://www.campinglebrevedent.com/fr/presentation.htm 

and the final destination...

http://www.camping-le-raguenes-plage.com/en/

we can't wait! We are going from 4th - 20th July.