>> "a junk pile next to an old barn..."
>> "if done right that could look awsome..."
Dude! That would be like - SNAP! Enclosure Makeover! 
Use weathered wood panels for the backdrop - you could get pics of an old barn, or real wood!
Have a broken-down wagon wheel for climbing. An old enamel cook pan for water. Some kind of rusty-looking implement, like a shovel or a hoe, and maybe a watering can on its side.
Use some kind of earth-looking substrate, like coconut fibre. Oh! Don't forget corn stalks!
To top it off - have, like a sound system, and play barnyard sounds, cows, chickens, etc.

LOL - Sorry for poking fun, but this is something I've been considering doing myself - you stole my idea! If you really want to see what cornsnake habitat looks like, and you live on the east coast, just go out to the nearest farm with woods nearby and there you are. Shoot, just go out in your backyard.
Kindest Regards,
John D.
-----
I am so not lesdysxic!
0.1 Creamsicle Cornsake "Yolanda"
1.0 Bairds Ratsnake "Steely Dan"
0.1 Desert Kingsnake "FATTY"