One thing I noticed at the end, right after Alice runs off after waking up, is her sister’s recollection of Wonderland. Exactly how did her sister know about everything that happened? Has Alice’s sister been to Wonderland before? It certainly seems so.
The sister also seems to be the only one who mentioned the name Wonderland, too. I get the feeling that Alice’s sister has been there before, with perhaps a similar adventure. She remembered some specific parts of the journey, such as the Gryphon and other characters. If Alice’s sister HAS been to Wonderland, it’s unlikely the adventure is really a dream like Carroll tells us.
But this recollection of Wonderland was in a dreamlike state (from what I’ve gathered from the text), so maybe it really IS a dream… who knows? Perhaps Wonderland IS real, and many people end up going there? Perhaps her sister was there while Alice was there, as there were a few times where things were moved around, such as the golden key in the beginning. Or maybe she heard Alice sleeptalking about Wonderland? What do you think the reason for Alice’s sister’s knowledge of Wonderland is?
Darcy S.
Connor S.
Devon H.
Morgan P.
Scott Mitchell
Alice's Pack of Cards 
It reminds me a little of Lion, Witch and the Wardrobe and how the siblings pass on the information to one another about the ‘other land’.