Calais > Antwerp > Hamburg > Copenhagen

Have used up all my annual leave for this year so thoughts are beginning to turn to next year's plans. I've got friends in Antwerp, Hamburg and Copenhagen and figure it might be a smart plan to try and tie them together...

i realise this is one of the most built up corners of Europe and would be keen for a journey that would provide some interesting attractions, whether it be environmental, architectural or cultural.

putting in the destinations in Google suggests taking an inland route but figure there's also the North Sea Cycle Route along the coast. Any thoughts or recommendations?

Calais to Bruges is pretty straightforward along the coast. You should get a tailwind for the 70 odd miles. To get to Antwerp can recommend going via Ghent. Lovely city much like Bruges but without the crowds. There’s no shortage of wonderful market squares in that part of Belgium
Use http://www.fietsroute.org/cycle-node-planner for Belgium to help as it shows the different road types and will take you along miles of cycle only paved routes. It seems to only be in English on the pc version.

Should add that the section from Calais to Dunkirk is dull as dishwater. I’d get the ferry to Dunkirk personally.
Riding down to Ypres and the WW1 memorial is really easy too and extremely moving once you get their and tour the battlefields and memorials. The 8 o’clock ceremony at Menen Gate is unmissable.
We did this as a club ride last year to mark the centenary of the armistice
https://www.strava.com/routes/15787565

I just did this exact route myself, then carried on up to Stockholm.

I got the ferry to Dunkirk as Alan mentioned, was a very easy ride through the town to the Belgian border. I used OSmand mainly for routing. It proved pretty faultless over the trip, only a couple of dodgy bits and dead ends.

I was advised to go inland as a lot is reclaimed land above Amsterdam, I visited a friend in Rotterdam then headed to Deventer (a beautiful small city with an old centre) The ride through the De Hoge Veluwe national park was very nice indeed.

Thanks for advice @Alan_tbt and @pj2606 gives me some food for thought

Depending on what your interests are, and how fast a tour you want:

• Obviously Belgium is great for beers; if you wanted to head from Dunkirk to Ypres then the Trappist abbey at Westvleteren is on route, as is the hops museum in Poperinge.
  
• The Belgian national museum of cycle sport is in Roeselare, between Ypres and Bruges.
  
• Bruges, Ghent, and Antwerp all have excellent museums and galleries - the Plantin museum of printing in Antwerp is world-class.
  
• If you're not a GPS user: I've not used the nodal system in Belgium, but my experience of Dutch cycling is that you'll be ok with a 1:200-250K map and just following route signs to the next town/village - it may be a bit slower, but the cycling's all so pleasant it doesn't matter.
  

You can go from Calais to Veurne on https://www.openrunner.com/r/9794574. From Veurne, go to Bruges, then along the canal to Sluis & up to Breskens to take the ferry. The default route generated by https://www.fietsnet.be/routeplanner/default.aspx is quiet good for this bit. After the ferry, use the route from the Race around the Netherlands up to the German border https://ridewithgps.com/routes/29581779
. I never cycled the bit through Germany, but of course there is the north sea cycle route you can use for that stretch.

If you do go Calais/Dunkirk to Ypres then as suggested Westvleteren is indeed en route. Even better and very close is St Bernardus brewery in Watou - has a lovely guesthouse (https://www.sintbernardus.be/en/guesthouse-en) you can stay in, and as of this year, a very nice roof top bar/restaurant (https://www.sintbernardus.be/en/barbernard-en)- highly recommended.

This V2 launch site en route to it as well is incredible and well worth a visit: https://en.wikipedia.org/wiki/Blockhaus_d%27%C3%89perlecques

Thanks for this. Very nice.

Ta - have added those to the notes for my next tour!