Here's an example of a polypropylene cage setup - here for a yearling N. Mexican Pine Snake (Pituophis deppei jani). This was put together before I acquired the snake, and after reading up on (1) the snakes natural environmental requirements and (2) how to meet those needs with a good enclosure (e.g. these articles at anapsid.org).
Since this photo was taken, the lamp has been elevated using a more secure (and more attractive) metal stand. Though not visible, there's a screen vent cut into the lid, held secure with some flat L brackets from the hardware store (melted holes for screws and wingnuts). The four clamps are for added security and - like using two thermometers - are probably overkill. Better safe than sorry 
The hides are now 2 modified flower pot bases (one above a heat pad, and one on the cool end) with some pieces of cardboard spanning the two hides for added terrain. Heat pad is on a Herpstat ND thermostat. I currently use aspen over paper (and over the hides) for substrate. Finally, a cleaned, baked branch and a store-bought fake vine for something more to climb on.
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