I've posted on this before, but make sure you don't neglect thyroid, breast and perioperative care (including pre-operative clearance and ICU-ish (i.e. recognizing PE with blood gas values, ARDS, etc.)
I used NMS (the first few chapters are necessary) and did well, even for my first rotation (although, ours is 12 weeks long). Make sure you do as many questions as possible.