For outdoors the ground tends to work fine. For the indoors, I would recommend coco coir or cypress mulch. I like coco coir but you can get cypress mulch for cheaper. It just depends on the size of the enclosure. As far as spicing things up, you can add stones, little sticks, small logs. I have a mechanical waterfall that lights up in mine. It looks pretty cool.Any one able to point me in the right direction for what soil type/ terrain I can put down in my horse fields outdoor run and his indoor table to try and spice things up for him a little bit? Thanks!