Hi account4fun, did you already see the website of the castle?
I think it is worth to see and it is on my schedule for next year, because they close it mid octobre. It has a big park which I expect is nicer to see in spring than in automn.
The various historic rooms of the museum should give you ideas about noble Bernese lifestyle from the 16th to 19th century
the elegant Summer Hall has furniture style LouisXVI
the empire room has furniture from the Grand Duchess Anna Feodorovna of Russia
As for the lakes: A scenery you see on the website of the castle is not possible on Lake of Brienz, because the mountains around Lake of Brienz hide the spectacular ones like Eiger Mönch and Jungfrau.
Edited: 2:20 pm, October 01, 2012