Route planning tips...

[gravitysucks]

I'm potentially got a few friends wanting to spend a long weekend out climbing / walking in the alps end of the summer but as I've got a week to play with I thought i'd pedal out there to meet them.

A very rough plan is to get a flight to either Rotterdam or Antwerp then pedal to the foot of the Eiger in Grindelwald which will be roughly 1000km depending which way I go.
I've never done a long tour before so have no idea where to start, is it simply a case of deciding what I want to hit en-route then figuring out joining the dots or is there a better way to ensure the route I take will be good enjoyable riding.
I've put Antwerp --> Grindelwald in ggogle maps and then dragged the route so it goes through Ghent, Roubaix and then all of the obvious national parks on the way to the alps. Give me a route of 1090km.

I'll be taking the gravel bike with bike packing luggage keeping gear to a minimum and bivvying all the way there. I'll pack up a tent, clothes and climbing gear and ship it to a campsite or hotel in the alps so I can arrive and (hopefully) have all my gear there ready to spend a few days in the alps before flying home.

So come on, give me some top tips!

[Mariner]

EV15 the Rhine route looks like it could be something you could build around.
http://www.rhinecycleroute.eu/

[gravitysucks]

Nice one looks like lots of ideas and sections I can grab from that!