Well carpet isn't exactly "natural" looking, now is it? I mean, when was the last time you saw Mohawk shag in the woods.
Shredded aspen is the most common substrate for corns. Most cornsnake owners use it. Its nice looking, nice smelling, they can tunnel through it, cleanup is easy, and its affordable.
If you feed him in the viv, you might want to not do that with a particle substrate that he could ingest accidently. For feeding place him a plain plastic container. When he's done, put him back in the viv.
Reptile carpet is nice for small lizards, but I found it to be a pain with snakes. They were ALWAYS underneath it, which if you use an under tank heater, they can burn themselves if you're not using a tempreture controlling device. Or slithering around underneath they'd spill the water bowl somehow, and you have a wet mess on your hands. Snake poo is also more watery than anything, so it soaks in and you're constantly washing it seems like. And its expensive. I don't care what they say, when you wash it and air dry it, its never the nice flat shape it was when you bought it.
Hope that helps!