Check out the UNC Gillings School of Global Public Health-- http://www.sph.unc.edu/prospective_students/intro/ --I am an RN, 18 years in family practice, completing my second semester in an MPH in Public Health Leadership/Global Health Certification. Same interests as you; I now have more contacts and paths to choose from than I ever imagined. The nice thing about UNC is that it offers incredible flexibility in terms of residential vs. distance programs, and is ranked as the #1 public (vs. private) public health school. Good luck! (And I am trying to figure out DrPH vs. PhD vs. PA as well--don't know yet. I imagine DrPH)