I booked a tour, which is only done during the weekend!.. The current building dates from the 17th century and is not as big and impressive as palace 't Loo in Apeldoorn (though it was designed by the same architect). It has some nice rooms all in barok style. In the garden of the castle they hold theater plays and there are also expositions in a small part of the building (but if you go to these you only see a very, very small part of the building and not the nice rooms so beware of that!).
The tour lasts for 45 minutes and is not expensive EUR 5,50 for grown ups.
I looked at the site and they say that it is not certain that they give tours each weekend, because the caste can be rented for weddings and parties, so check first!.
It was an entertaining tour, but I have seen more impressive castles/palaces. Still it is a good alternative if you stay in the Utrecht region and it is a nice and green area, nice for a walk afterwards!.
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