Here comes some more updates. I have done a fake rock background, and it truly looks fake, lol. I really need more practice. XD
It's made in four sections that is simply attached to the plywood so that we can take them away if we need to move the enclosure. I think it would have looked a lot better if I have done it inside the enclosure as a whole section but that's a price we have to pay.
They are made in the most classic way using styrofoam and grout. It's actually five sections. I was working at my parents summer house and the last piece didn't fit into our car so I couldn't take it with me.
Also added some more plants that really makes the whole thing look more alive. I hope she likes it.
And some size reference: