TBH, if I were doing it again, I'd try to come up with a plan that stayed inland and avoided Dunkirk
Can't remember where I got it from, but if you google around a bit you can probably find this inland route along the canals:
Having now done this route, I heartily commend it to the house.
View track here:
http://www.gpxeditor.co.uk/routes2/users/nikki/Dunkirk-VeurneLearning point: don't do this:
Get left once you're past the booths at the port. If you stay on the right hand side, you get filtered around the roundabout and have to huddle at the point where the railway crosses the road until there's a gap in traffic and you can head back to get back on track. (The track doesn't quite tally up with the roads in that shot - check out the map for satellite views etc.)
3km after leaving the boat, and after having hung a right down what looks like an unpromising gravel track*, you're on roads like this:
*It's fine once you're round the corner
Pretty much that all the way into Belgium.
The potential gotcha is there aren't a lot of opportunities for food, so might be wise to have stuff with you.
Otherwise: idyllic.
