This isn't even the palace; this is just the magician's house.
Because I am not an architect, I have haphazardly mixed a bunch of different levels in one plan, based on the places where my characters will be spending the most time. (To be honest, I would like to see romantic leads spending more time in the kitchen, but I'm afraid I'm defeated by the write-what-you-know thing.)
Why is it that although I know nothing about architecture, I insist on doing these every time I want to do a comic? The answer is because the art needs to flow properly, and to achieve that I need to know where everything is, and get used to it. Also, I am obsessed with production design.
Some more 'setting' sketches: