All of the fields you mentioned are lifestyle friendly, which of these you choose does really depend on "which you like best".The residencies are low key as far as nightcall and hours worked per week as resident and attending goes.The problem with Derm is getting in to it(VERY high demand for VERY few residency openings),Rads is easier but still highly competitive.PM&R is not difficult to get a spot if working with patients who have chronic neurological/spinal cord and similar injuries appeals to you.Occupational medicine is a very administrative field which involves dealing with workers comp and related legal issues,it can be lucrative for some.