Somewhat off the beaten track... but one of my favourite places in the Hamburg area is a little town called Ratzeburg. Unfortunately it's not quite as easy to get to as Lübeck or Bremen as there are no direct trains (you need to change at Büchen - or detour via Lübeck or Lüneburg)

Couldn't find any information in English, but there are some pretty pictures at www.ratzeburg.de - click on "Stadt Region" (left-hand side of page) then "Ratzeburg Ansichten" (top right-hand corner) (The site uses frames, hence no direct URL for the pretty pictures)