You need to get a hygrometer so you can monitor the humidity level in the cage... the cage needs to stay around 60% humidity all the time. (yes, misting the cage will help to keep humidity up)
I would recommend that you not user that scull as a hide. The eye sockets will become a hazard as the snake grows. These hides are the best on the market (and cheap)
http://www.reptilebasics.com/hide-boxes
The small size should be about right.