The cage style isn't ideal for the reasons mentioned, but it's workable with a few adjustments. I would fill it up with substrate up to the first level, and try to construct some sort of fence for the top level. My Roborovski has no depth perception and will run straight off edges if there isn't a barrier to stop her. You could get a platform or a large house with a flat roof to set the wheel on, so that it's above the substrate level. A few options from Amazon:
https://www.amazon.co.uk/Trixie-Natu...0089868&sr=8-8
https://www.amazon.co.uk/Trixie-Natu...0089868&sr=8-5
https://www.amazon.co.uk/Trixie-Guin...089868&sr=8-10
https://www.amazon.co.uk/Trixie-Wood...K936Z9GBD4Y51Q
That's a good idea to use one of those burrowing boxes for the sand. I might try that myself. I like the branches and bark too.