I thought the surgery shelf was the hardest one. You have to study surgical topics, but you need to know a little medicine too, so I think that throws people off. I felt like a lot of questions on my exam boiled down to: Is this a surgical problem? If not, what is it? And also: If so, does this problem require emergent surgical intervention? Or can you manage it conservatively?
I used NMS and CaseFiles, and used textbook chapters for wound healing, post op infections, post op complications, hernias, sbos, FEN. Don't remember what text I used, but I think any big surgical text would do, like Lawrence. PreTest I thought was too picky so I stopped using it. Recall= good for pimping only in my opinion, I don't learn well from their format. Got an 87, which I was both surprised and very happy with.