Yeah, if she hasn't asked yet, then she may not even expect it. For all you know, she might have made her other plans already.
Now, personally, if I were in that position, I'd want to be helpful but not at the expense of my own vacation. If it did turn out that she's looking for assistance, I might say, "I won't be up at that time, but would you like help paying for an Uber?" But of course that's not socially obligatory. It's just the sort of thing I myself do because it sends a message of good will while also establishing boundaries.