The tours during the day are around an hour, the ones in the night are longer. Then there is waiting period to get your tickets scanned, get on the bus and the ride to the castle. What I can say is that the time flies, you don't get bored for a min. Check the website for the actual tour times. We went to the one that started at 7:10 pm (bus departed the visitor center) and we were back by 9:30 pm.
Various times day and night are available. Please check their website for more details.
You're also able to walk around and photograph the property on the outside as long as you like after the guided tour. As long as you catch the last bus back.
It's according to what tour you want, their website is very helpful
They have multiple timings and it's all day long. Tour itself is left than 1 hour but it takes 3.5 hrs from start to end.
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