Honestly put as little as possible inside the cage. The more you have in the cage the more you have to clean/disinfect on a regular basis. Remember that cage decorations are for you and not the snake.

This is how I house all of my Ball pythons:



This has all of the necessities Proper temperatures/humidity, good hides, and a water dish. anything more is for you and not the snake.

Make sure you avoid anything that the snake can get stuck in/on and materials like wood that won't handle the humidity well long term.