She feels secure inside. You should be flattered!
You could try putting her litter box outside if you have a covered porch or something like that. Eventually if she goes outside you may be able to get rid of the litter box entirely.
If you really want to see a cat that sleeps in strange positions let me recommend this thread from @pipdzipdnreadytogo
https://www.backyardchickens.com/threads/its-time-for-me-to-admit-i-have-a-problem.1508954/
I have four cats of my own but I am hooked on this cat and his sleeping positions.
I have several. Not just because I have several cats but because I keep misplacing them and buying new ones!
The one I like best is called Furminator. Amazon link below. And I am serious about the amount of fur - I had a session with one of my cats recently and I created a whole new cat's...
You can get a cat comb with metal teeth that really gets at the under-coat. Masses of hair comes out and the cat LOVES being combed and will go completely nuts purring and rolling over and so on. As your cat goes outside I strongly recommend doing this outdoors because it is hard to over state...