Time travel... I've never really given much thought about it. The rules of time travel in KH had confused me just as much as the whole datascape situation with KHUX to the point I wish they didn't introduce either.
I would like to think teleportation (just mainly talking about the dark corridors and the portals Sora, Terra, Aqua, and Ven use when getting to Olympus and the ROD respectively.) deals with the person actually having a visual inside their mind of where they want to go (so basically they do know the place they are going to. Like how Sora was told to use his heart to guide him to Olympus in KH3.) Teleportation has, a lot of the time, been related with being able to bend or manipulate space which explains how Keyblade wielders are able to open corridors to space itself. It's of course like a door/gateway to space and other worlds, so why wouldn't a Keyblade be able to unlock it? Of course, I'm just spit-balling and talking out of my butt because things like this have always been kind of hard to rap your head around.