Think my time scales might be problematic as I’m wanting to head out in May. Might re plan and do Calais to Vianden and then off to the ring and surrounding areas.
I tend to get off the autoroute and use departmente roads to Langres. Stay the night and then go via jura mountains. Hook round by Cern to avoid going into nazi swiss land. Then wind my way via Annecy. But thats on bikes. Edit: there are so many wonderful roads on way to alps, you wouldnt wish to miss them. My fave is up over jura's from Champagnole and down into Gex.
As said, trying to get my mates who make Boris look organised sorted is proving an impossible task. Think I’ll be shortening the trip to Vianden and The ring
Believe post brexit there are problems with import and export fees if you are using a transport company and not accompanying your vehicle. Alternative - could be ferry to Santander or Bilbao and then Picos mountains and / or Pyrenees? Ferry back or blast up thru France?