Here are the three routes in a .gpx format, so Garmin and TomTom devices should be able to read them.
On day one we go near enough SSE, then cut straight east to Ypres, passing through or close by the Menin Gate. We then go to the cemetery at Tynecot, the largest of the WW1 burial grounds. I understand that a part of the site is undergoing restoration though the cemetery itself is still open.
We can then head very nearly south past the Newfoundland memorial between Lens and Arras, then on to our hotel in Arras itself. This will be about 130 miles over the whole day.
Sunday, we can head due south, to the east of Albert, to Corbie on the Somme river, then pass north west of Amiens, turning due west then north up to St St Valery, where (with luck) we can have lunch. That is about 130 miles, with a coffee stop somewhere.
After lunch, it's straight north, skirting to the east of Boulogne and back via the Channel coast road, via Wissant, to Calais and the train. That's about 85 miles.
So, on Sunday we are looking at a combined mileage of about 215, in a what is a big U-shape from Arras up to the coast. Total mileage in France over the weekend, about 345 give or take a bit. There will be a bit of everything in it, some motorway, some dual carriageway, some N and some D roads.
Cheers, Richard
File hosted on Dropbox:
https://dl.dropboxusercontent.com/u/14126843/FINAL - MARCH - ARRAS - TWO DAY.gdb