If you want to up the ambition a little bit, you could maybe look at something like this, from Calais to Roscoff. Viewed in context it looks commendably complete, taking in the full sweep of the French channel coast, giving it a touch of grandeur. The route is for illustrative purposes only and could certainly be improved in many places, but I've been careful to include the Alabaster Coast north of Le Havre. It comes out at just under 450 miles
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