LOL they will arrange how they like. I'd be inclined to try and accomodate her. Give her a nice deep substrate as she seems inclined to dig in it. I like the idea of the buried tube as long as you can keep an eye on it in case she pees in it or it hasn't adequate ventilation and gets soggy. Put her sand box and food on the other side of the deep pile. If you can, you might try using a bendy bridge on its side to divide the cage so you can keep the deep substrate on one side more easily. Depends how she decides to rearrange that, no guarantees.
Oh and I'd love a before and after picture.
