“Oh, what a world! What a world! Who would have thought a good little girl like you could destroy my beautiful wickedness?”
Dorothy has no parents, although she does have a supportive aunt and uncle. And she enters the otherworld not of her own volition but simply by mistake, having been caught in a tornado. (In the 1939 movie, she is dissatisfied with her life there and even meets an initiatory figure in the guise of the magician, and getting trapped in the house when it blows away is partly her own fault – a departure from the novel but more in keeping with the Girls Underground story.)
Her only companion at first is her dog (it may be relevant that her dog is male, as are all her companions – frequently the case for girls underground, even when their companions are animals), although she picks up three more on her way to her goal (unlike Alice, who seems to enjoy exploring the new world she finds, Dorothy is more concerned with getting home again). Her adversary is, obviously, the Wicked Witch of the West (and her minions, including the flying monkeys), although in a way the Wizard himself presents as an adversary at first. The female adversary fits better with the original, younger version of Dorothy. She also has a brief episode of forgetting/being drugged when they all fall asleep in the poppy field.
Dorothy is separated from her companions when she is captured by the witch, and must face her alone for awhile, eventually defeating her. She then must expose the fraud of the pseudo-adversary, the wizard. Though it is neither of these triumphs that ultimately is responsible for her return home, but rather the power of the silver shoes (ruby in the movie, to make use of the new Technicolor), which she had possessed from the beginning.
The 1939 movie includes one common Girls Underground element that the book does not – the echoing of people and things from her home in the “real world.” The farmhands are her companions, the travelling magician is the wizard, the wicked witch is the nasty neighbor. Unfortunately, this is taken further and leads to the “it was all a dream” ending (for perhaps obvious reasons, since I see a current of spiritual truth in this plotline, I prefer examples which do not undermine the reality of the adventures), her experiences chalked up to a bump on the head. Whereas in the book, Dorothy returns home to find clear signs of her long absence, and an aunt happy to see her again after thinking she was lost.
The Annotated Wizard of Oz
The Yellow Brick Road (home of not only an entire Oz-themed store – which I was fortunate enough to stumble onto during a cross-country road trip – but also a local Oz festival)
The Wizard of Oz (official site of the 1939 movie, now celebrating its 70th anniversary)
The Wonderful Wizard of Oz Website
Dark Side of the Rainbow
Full Text at Literature.org