2scents — Cinderella is right, and it also depends on the seminary. Your statement that “most” kids are involved in these things is just absurd — Ben Yehuda couldn’t hold “most” of the yeshiva and seminary students in this country! I went to a serious B.Y. type seminary in Eretz Yisroel and stayed on a second year as a madricha, and neither year did anyone in my seminary get drunk. Curfew was strictly enforced (the doors locked and you had to sign in in person, even on Motzei Shabbos), and I don’t know of anyone in my sem who hung out on Ben Yehuda. I did have friends from high school in different seminaries who became part of that scene — but these were the same girls who would hang out in America at pizza shops on Motzei Shabbos, etc.
RabbiRabin — Almost everything can be gotten here for a price (even zip lock bags!) . You just need to determine if you’d prefer to save the money by bringing it or avoid the shlep and spend a bit more.
I do advise bringing your own deodorant and sunscreen, both of which cost a fortune here and offer you much less of a selection. Also a box or two of really soft tissue for when you get a cold. (Kleenex is available here, but only the basic versions, and noses can get irritated pretty quickly).
Coming with a list of people she can call for Shabbosim is also helpful — maybe an older friend, neighbor, or relative can give your daughter numbers of people she knows or met who enjoy hosting girls.
Good Luck!