That's a deal and the beers will be on me. Diekirch will be near the end of my journey, so mid to late August if that fits in with you? Would be good to meet up with a many people as possible on my trip.
if travelling to La Coupole than the Batterie Todt (Atlantic Wall) museum - at Audinghen/Wissant on the coastal road between Calais and Boulogne - is also nearby...the museum is housed in one of the four casemates. Also on this road you should stop for a few minutes at Cap Blanc Nez, which is where Goering stood on the cliffs and looked across to Dover (scene recreated in the Battle of Britain film) http://www.landmarkscout.com/battery-todt-audinghen-cap-gris-nez-france/ the landmark scout site will give you a few other suggestions too
Non WWII, Trier, Germany near the Lux border is the oldest city in Germany. Once part of the Roman Empire, there are lots of interesting sites.
I've managed to get my map itinerary into order and a very crude route added. For some reason Google will not let me finish the route but it's the last part, so fairly easy to work it out. If you know of anything along my route that I should see or cool people to meet, let me know. https://mapsengine.google.com/map/edit?mid=zcVaUeSKtoTA.kyEKcCqrDGKU