I think aspen bedding is probably the best all-around colubrid bedding. I think you should not use the cage carpet - not that it is bad, but the snake will want to crawl under it, and will be in contact with the glass with no buffer inbetween. If using an undertank heater, it is nice to have some substrate over it.
My favorite formula for colubrids: aspen bedding and an empty cereal box as a hide spot. Inexpensive, easy to clean/replace, and the snakes feel secure. I always use paper towels for baby snakes and move to aspen after a few months. Good luck with the new snake.