citow is okay, though probably getting a bit outdated. there’s another book by moore and psarros (definitive NS board review) that is a quick and easy read. i’d definitely go through the previous edition of osborne at least once, as well.
the night before, memorize your peripheral nerves, cranial nerves (sandoz course), enzymeopathies, and brachial plexus (i guess that’s peripheral nerve). these are all easy easy points on the boards and shouldn’t be missed.
board content is variable. sometimes it’s anatomy heavy, other times it’s something else. once there was a lot of cerebellum questions; another, it was the thalamus.