I did the stretch from Seysel (sp?) to Geneva. It was pretty much totally unsignposted. Will from this site sent me some leaflets with the two stretches that i was doing on in more detail, very happy to post them if you pm me your address.
It would be pretty easy to buy a 1:200,000 map and trace the route from the website onto the map with a highlighter, we did that as well and it was good. The route itself was good, and I'd recommend it as a route out of Switzerland even if you go elsewhere quickly.
The Swiss bike routes are in a class of their own and heavily used. Fantastic to see!