The castle is home to the Hall Art Foundation, a great stop for art lovers. Changing contemporary art exhibitions await you within the castle walls, and a sculpture park is spread throughout the grounds. All information about opening hours and current exhibitions can be found here: hallartfoundation.org/de
Derneburg Castle itself is unfortunately not open to the public. From the parking lot – by the glasshouse – the path leads a short distance around the buildings of the former estate. On the east side behind the buildings begins a small circular hiking trail around the entire complex, the so-called Laves Cultural Trail. From here, you can embark on a short journey through time, exploring the history of the family of the first Derneburg Count, Ernst Friedrich Herbert zu Münster, and the Hanoverian construction director, Georg Ludwig Friedrich Laves.
It is best to park in the parking lot opposite the glass house, then just head towards the castle and follow the really good signs for the Laves culture trail.
Passing old trees you get to the tea house relatively quickly, then a little downhill to the pyramid mausoleum, next station the fishermen's houses. Then follow the road a little and keep right after the bridge. Passing further lakes you will then get back to the starting point.
Now you could think about whether you can end the round in the glass house with coffee and cake.