Driving thescenic route through Switzerland?

Afternoon everyone!

I have received the following question from a fellow member:

I am travelling from the U.k around 23 May in a motorhome 23 feet long from Dunkirk? thorough Belgium perhaps visiting Bruge Then going a scenic route over the mountains of Switzerland ending up around Monaco. I then want to tour the coast beyond St Tropez and return thorough France perhaps to Caen taking 31 days. in total. Are there any members who have done a similiar trip who could give me some advice,Thank you Mister H

Mister H is a bit concered about mountain passes in Switzerland and the general conditions of the non-motorway roads, as he wants to take his time and not drive on motorways all the way. If you have done a similar route it would be good if you could offer some advice.

Many thanks Hazel