I'm so glad you enjoyed Hohenzollern, and that you had good weather that day so you could enjoy the views (although it is also extremely atmospheric in gloomy weather!). After 2.5 years in Germany and many, many castles, Hohenzollern remains one of my all-time favorites. In my experience (at least 3 visits that I can recall) they have never offered English tours - they simply don't get enough English-speaking visitors. But that's one of the things I love about it - it is still relatively undiscovered.

Meersburg is definitely better on a sunny day. The lakeshore promenade is lovely and the castle is very interesting (the oldest continually-inhabited castle in Germany).