www.cornsnakes.com is AMAZING!
I have a corn as well. You will probably want some more private hides (those half logs are not dark enough; your snake will most likely spend her days under the substrate like that). I don't think you *need* to cover the sides and back with dark paper - although you can if you'd like, of course. My corn personally doesn't care either way. They also like to climb I find, from my own and other's experiencesthat foliage is a good idea!
The day/night cycle is a good idea too, as long as it doesn't get too hot (as mentioned above). I wouldn't use anything over a 13W bulb myself, especially with that size tank, unless your room temperature is particularly below average. The nice things about corns too is they can handle a night time drop in temperature, as low as 15C (59F) I have heard. However I'd definitely get a UTH with thermostat and set it at 85F though, again as mentioned already.
They are quite active snakes once comfortable in their surroundings, so you should have a blast. Best of luck to you!!
P.S.
Please, please, PLEASE get some screen locks for that lid! Or at least put some heavy weights/books on every corner for the time being. You'd be surprised how corns can push those things, as thin/weak as they look. They aren't easy to find either!![]()