Z-Man, my recommendation is to pick a specialty you like, then pick a job with hours you like. Better than to pick a job for the hours and not enjoy it at all. That said, neuro-surgery may not lend itself well to part-time work! Probably, the surgical specialties are more committing in general.
Even in family med, you can have a job working 1-2 days a week or you can work 24/7; it's largely up to you. There are also jobs where you kill yourself for one week, then get three weeks off, repeat.
Another option to consider if you think you'd like to have huge blocks of time off is locum tenens. You can work 6 months a year and take 6 months off. (Or, 4/8, 9/3.) Balance time and money how you like.
Layne