For 800-yen (500-yen with the annual pass), you get a 35-minute trip out and back from the Free Zone area at Huis ten Bosch. Shortly after leaving the dock, the boat's crew will open up the bow area for guests 4 and up to scale up and and back down. The first picture on this post is a view from the top.
I would advise flat shoes for this. You have to balance on a rope to get to the top.
Don't worry, there's a net to catch you if you fall. The net won't catch your camera though. I had a death grip on mine.