Hi all!

I'm in the very early stages of planning a bikepacking trip from the UK, through France, to Switzerland (Kandersteg, Switzerland, specifically). This is a solo adventure for charity , though I am open to having a partner if anyone is interested! This will be in June next year, for foodkind.org, a charitable organisation which provides food to refugee camps in Greece.
The entire trip will likely be approximately 700 miles.

For obvious reasons, I don't want to spend a lot of time on major roads, however, this is the first time I have planned such an adventure! Is anyone aware of some good routes that would lead me from the Northeast corner of France Southeast to Switzerland? Or indeed any nice routes through Switzerland, to go from the Northern tip south to the middle of the country to Kandersteg (just south of Frutigen)?
Also, any advice you can offer to a beginner bikepacker would be highly appreciated!

Thanks in advance,

Luke