Taking a dog to the South of France in Summer

Tintin

I am fed up of boarding the dog and considering taking her on a caravanning holiday to France in August.  We would like to go as far South as possible but wonder if this is too much for a labrador to cope with.  Much as we want her with us, we don't want
to put her under stress so would be interested to know how far is not too far with a dog on board???