Exactly. In fact, this is also correct: "Mit csinál most a lány?". But for example "Mit csinál a most lány?" is incorrect!!
Does the Hungarian sentence carry the same connotation as the English sentence "Now what is she doing now?...",
I mean like, "Oh god... now what is that girl up to?..."
No, not really. I guess what you think of is "Mit csinál már megint a lány?"
Not with this intonation we have in the audio. But, on a second thought, I think you are right and this question could be asked to convey the connotation you mean..
I can't decide whether "What does the girl do now" should also be a correct translation or not. Any thoughts?
this word order is going to kill me when it will be needed to reverse translate the sentence.
The key is the importance. We put that word in front that we want to emphasize. You have to consider some grammatical structure, like not taking apart the article and the referred noun (Mit a csinál most lány, mit csinál a most lány are both WRONG) and choose the most important part of the sentence.
It's a good example of a question in Hungarian: question words do not have to be in the sentence-initial position, but you can hear that the speaker's pitch is going up on the question word, which comes just before the verb (this is the "focus position"). Listen to this a couple of times while you see the sentence, and you'll get a good feeling of what questions can sound like in Hungarian!