Caravanning in Switzerland

I am planning a trip to Europe this summer towing my caravan (6.8 metres) and am proposing a leisurely drive down to Italy (Desenzano del Garda) through Luxemburg (Gritt) and Germany (Rudesheim am Rhein) then onto Switzerland (Lazy Rancho 4). Coming back I am proposing to go west into France (Le Coin Tranquille) before going north. Looking at the roads on google maps, all seem ok except those on the way from Lazy Rancho 4 to Desenzano del Garda. The route east from Interlaken to the E35 looks tortuous and I can't see an alternative. Has anyone driven that road? Am I likely to have difficulties getting round the hairpin bends with my caravan? My tow car is an adequatley powerful 4 x 4 so climbs shouldn't be a problem.

Any advice would be gratefully received.