But the basic idea was that a wizard in fiction could fold time and space to form a pocket. I'd like to figure out the reality of what might actually happen to decide where I need to alter stuff. What would the wizard need to do in order to exist properly.
You want the wizard to change the topology of spacetime. This is a bit more than just folding (see below).
Let's say that a human removes himself from time and space and remains at a specific location without existing in that location.
I don't think that that's meaningful.
Were he to step out of that pocket and back into normal space, he would appear exactly where he had left.
If you can step out of the pocket, it's not really outside normal space (see below).
I guess the original idea came from whats-his-name's theory about faster then light travel. He theorized that if you could bend space around yourself (yourself being a space ship I would imagine) you could have space act as the infinite source of energy to propel you. Kind of like squeezing toothpaste out of a tube 
I think you're thinking of Gene Roddenberry. That's his explanation for warp drive, iirc.
So, thinking about space and time. Space and time -- or rather, in modern parlance, spacetime -- is what is called a "manifold". This means that it doesn't do anything weird anywhere. It's also a
single manifold.
An analogy that I usually hate but which suffices here is that of a bedsheet or tablecloth -- such things are both manifolds (except that they're not infinite, but whatever). Imagine a sheet that has no irregularities or flaws. No holes, no tears, no loose threads. For the most part, our universe works like this. Well, imagine if you had a bedsheet, and also a napkin. They are not "connected" in any way: a bed bug on the bedsheet cannot crawl onto the napkin. Your "pocket in space" is sort of like this napkin: it's not connected to normal space. The problem is that there is a universe outside the manifold of the bedsheet -- the bedroom -- so it's meaningful to talk about the bedsheet and the napkin which are in no way connected, but there's no universe outside the manifold of our universe.
At least, maybe that's what you want your pocket to be like. It's not clear. You have to decide on one of the following options:
1) There is (in spacetime) a two-way path from our universe to the pocket. In this case, the pocket is part of our universe. There are a lot of sub-options here: it can be a distant part of our universe that's connected by a wormhole, for example.
2) There is (in spacetime) a one-way path from our universe to the pocket. This is basically a black hole; you'd have to come up with some explanation as to how the inside of the hole isn't a singularity.
3) There is (in spacetime) a one-way path from the pocket to our universe. This is basically a white hole; you'd have to come up with some explanation as to how the inside of the hole isn't a signularity.
4) There is no path (in spacetime) from our universe to the pocket, or vice versa. This case is not physically meaningful since if the pocket isn't connected to our universe, it isn't anywhere; it doesn't exist.
So, decide which option best matches what you're going for and we can discuss it further. Note that exactly one of them
has to match what you're looking for; pockets that are any combination of those options (perhaps at different times) are really just the lower-numbered option (2 and 4 is really still 2).