It is a small, Seven Sisters-y world, indeed. In fact, I already know two other Bryn Mawr alumnae at Princeton doing their Ph.D.s in the French and Spanish Departments, respectively.
As for our housing assignments, another friend of mine at Princeton, currently in the first year of his Ph.D. in Mechanical Engineering, told me that we would find out around mid-June. I have also been told that it is relatively easy for first-year students to secure singles in the New Graduate College since, as counterintuitive as it may seem, first-years are given first priority and since this dorm is comprised mainly of singles, in contrast with the Old Graduate College.
After my visit to Princeton, (let the record show!) I ended up changing my mind about the GC and opted for a one-bedroom in the apartments instead. Fingers crossed! And good luck to you all!