Join Date: Mar 2011
Location: Zaandam, Netherlands
Perhaps you have already left, just for people who might be wondering: I did part of the Danube route last year while cycling from Vienna to Zurich, the part along the Route Velo 6 route was very well marked and very well known with the locals. They see cyclists as a very welcome addition to their economy. It's hard to get lost and people are very eager to help you on your way.
Locally you can buy very detailed maps specific for cyclists with trails to spice up the otherwise somewhat little challenging route. Accommodations are generally very well catered for cyclists. There is no need to worry if you follow these routes.
Hope this helped.