I was told that the NPS has already issued the maximum number of permits for using the GW Parkway for other events, but that WABA is still working on it.
The BikeDC.net site (use the link in the first post in the thread) now says the ride is alive and well and the registration will start tomorrow, Tuesday, March 22, for the Sunday, May 22 ride.
I just clicked on the link in the first post and can get to the registration page. Unfortunately, the online registration is not yet active, but you can download a mail-in form. Price is up this year and the route has changed.