Diogenesister-it almost sounds like the Bible wasn't quite so black and white when this was written. (Ie not the later idea of absolute evil and good)
Or, the scriptures were being accurate in describing the snake's comprehension of the "mechanics" or functions of the spiritual world in relation to the physical one.
The 'navigation' part of the definition of aroom is especially interesting. Going back to the gnostic beliefs, the snake is described as being a benevolent figure who has the capacity to show a human being the path back to their divinity, aka become one with God again. This implies that the being, identified as satan to Christians (hence I assume the translation of the word into "crafty" or cunning), knew how to maneuver between spirit and flesh with ease.
In the garden of Eden, the snake claimed that Eve would be like God, which again is a concept associated today with gnosticism (this of course being a version of much older concepts). He seemed to be playing the benevolent role of the gnostics here, implying he had knowledge that could transform her.
The snake, as Genesis describes, did in fact posses wisdom and insight into the method of transforming from spirit into flesh and vice versa that made it stand apart from other spiritual beings that presumably didn't know how to. Where it lied blatantly was in claiming that a human could be like God himself.