I would find out if she is even interested in having a fwb first before you waste your time. If this is a case where she ends up liking you and wanting a ldr, you are screwed and likely not literally.
You have a good point, but directly asking her that question would be too forward, given that I don't know her that well. Also, I found out she's in a relationship currently, so she would not be willing to say "Yes I want a fwb" in writing. I think by saying she wants to hang, she's kind of saying she might be willing to bang. Which is the beginning of fwb. But also a ldr, which brings us back around to the problem.