You need to take a bus to get to the top of the hill where the castle is located. You can't drive up yourself, but bus ticket includes tour of the inside section of the castle you want to see (kitchen, bedrooms etc) then afterwards you can walk around the public areas (pool, garden) on your own
You can explore only surroundings on your own. To get inside you need to get a ticket, and there is no way to get on the territory without a ticket because they bring you there on the bus. $25 for any ticket/your, that's not so bad.
You have to book a tour if you want to view the inside. Pricing is reasonable.
On the way up, on the bus, we were passed by a private car. I asked the bus driver if that was a private tour, and he said yes. I wish I knew more about it than that. At the bottom, there is a gate that prevents anybody from driving up.
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