Tauck App
Hurray! The Blue Danube cruise (at least the 12 April departure) has been uploaded to the Tauck App!
I'm still exploring it, but have already discovered there are still items that need work- little things like the photo for Linz, Austria in "Destinations" is actually a photo of Salzburg and the Hohensalzburg fortress (the same photo as for Salzburg) and more substantive stuff- most names listed under "Destinations" > "Prague" > "Sights" are in Czech instead of English.
On the positive side, when you select one of the names a rather detailed description of the site and map showing its location pop up. e.g. By selecting "Nerudova ulice" you learn that it is a steep street located in the Hradcany district. It is named after Czech poet Jan Neruda and was the last leg of the "Royal Way." I guess that will force me to select and read each one! : )
The map shows distance from your current location; "Nerudova ulice" is 4450 miles away from me right now : ) Unlike Google maps, it doesn't provide routing.