Wonderland is a world that is Alice's dream. So, if Sora could travel to it then he went inside Alice's dream.

 

Mind=Blown

I guess that's true, but since KH is practically a parallel universe to both Disney Universes and Final Fantasy ones, it probably is a real world that happens to be similar to the dream Alice had. Of course, they never took that into consideration, soooooooo ye. Plausible.

I presumed Alice's dream was real just for the sake of not making her out to be a crazy mofo she was made to believe it was a dream so people wouldn't think she's insane and send her to an asylum with all this talk of singing flowers, grins with faces, talking doormice, mad hatters etc

 

Wonderland I would say is like narina, in the way that it is real, but you can't just buy a ticket to it.  A lot of movies play off on that "it was just a dream" when it wasn't.  

 

It's original title in the book was Alice's Adventures Underground (which influences the 2010 edition saying it's actually Underland instead of Wonderland), and you do access it by going underground.  Speaking of the 2010 edition, she gets a scratch from a Bandersnatch and it still visible on her arm when where leaves Wonderland.  She also makes the conclusion that Wonderland was memories of a place she'd been as a kid but a dream.  However that is for the Tim Burton version and not classic Disney version that we see in the KH series, Disney merged together the novels Alices Adventures in Wonderland and Alice Through The Looking Glass.  Lewis' unique literary style is evidenced through a free-flowing “dreamscape” story format, where Alice makes transitions from dreaming to waking and characters within her dreams are themselves dreaming (one of the questions at the end of Looking Glass is something along the lines "Was Alice dreaming about the Red King or he about her?"  

 

I'm going off on a tangent.  I don't consider Wonderland a dream.  

What if Alice wasn't dreaming? What if the dream she had was that she was dreaming and wonderland was real life?