You don't take gross anatomy? That might make that section tough.
If you can get your hands on the Boards application they outline how many questions per topic are covered in each section. For exp: there might me 3 questions out of 100 on the shoulder and arm, 10 Q on histology, 10 Q on neuro. sci, 50 Q on the Trigeminal N. You get the idea.
The best study aid for gross is probably the dental decks. Some anatomy is covered in First Aid for USMLE but head & neck is weak.