@Ren: There's a spot in White Night where it looks like a hole from the Nevernever (similar to how Wizards are suggested to get around), but it has what I would consider D&D Gate-like features. In Changes ... there's someone who looks like he can take a pretty direct path and has the power to pull it off (a non-wizard).
In general, I would assume you would want to "preserve a hospitable environment." That would mean air supply, sure, but that's elemental and easy. Most importantly, it would mean atmospheric pressure, protection from solar radiation, constant/habitable temperature, and more. If he poured the magic into making an "earth-like environment," he would need to capture all of the above; which, to some extent, are all aspects of earth's environment, already.
I think we can all assume Rashid capable of "big thaumaturgy."