Travelnut5

I am planning a Danube cruise with Uniworld for either May 19-26 or June 16-23 from Budapest to Passau. We will add on and go to Prague from Passau either with Uniworld or on our own. I need advice! Based on temperatures, rain, river water levels, and travel crowds, which month is best for the best experience? Do you advise doing the extension with Uniworld or on your own to Prague?