I think there are few private practices that emphasize intracranial surgery. For most private practice groups spine surgery is the mainstay. There are just not that many patients that need intracranial surgery to support a private practice surgeon that does that exclusively. Patients that get brain surgery are generally sicker folks and need more care afterwards. For a small private practice there just isn't the staff to do that. The more straightforward spinal procedures don't require much post-operative care. There are even some neurosurgeons doing this as day surgery now.
I think you should spend some time on a neurosurgery service (even as a student try and spend a day or two shadowing...not just in the OR but seeing the care required to take care of the in-patients) to see the variety of stuff that a neurosurgeon does.
Asking about hours and money (as most of your posts are about) before you see what they do is probably the wrong way to learn about neurosurgery. Spend some time and see what you think.
Neurosurgery is definitely very cool but there are many other ways to earn lots of money and work good hours.
I guess I'd sum it by saying regardless of what you do in neurosurgery, the money is good and the hours are long.
