You can only see the castle of WWHo, and from tower 3 it would be rooms even numbers ending 00 up to 48, and the higher the better, although i think it would be from 5-6-7 only as 4 has a lot of trees now,.
I would not depend on getting tower 3, unless you get checked in early, as the hotel was completly full when we where there for 10 days from 7th Jult to 17th July