Rhine River Cycle Route - Anyone done?

There's something every year called "Tal total", when the Mittelrheintal between Bingen and Koblenz is closed to through motor traffic and you don't have to use the annoying cycle path (narrow, badly-surfaced, sends you into some silly diversions through towns, and goes up and down a lot next to the road) but are permitted to ride in the carriageway. I wanted to do it this year (riding from Mainz to Koblenz and back), but it was cancelled because of recent storms which had uprooted trees and caused at least one landslip. I've never done it and for all I know it might be a little like London-Brighton if thousands of people turn up, but perhaps traffic is lighter than that, as it's not just one defined route. If I'm in Germany then, I'll try again next year.