That's not entirely true - both the queen's chamber as well as the descending passage are indeed mapped. There's a note when entering the descending passage: "This is normally blocked off to visitors, but we can visit in our tour!"

If you didn't get to them by clicking through the photos, you can click the lower left "Dollhouse mode" icon to get a 3d viewer, in which these things are visible. They are both included on the "guided tour" mode, however, if you just load the page and click through the prompts in the middle.