I did a paper on drones, and did a lot of research on them. From what I understand, only commercial use of drones is prohibited, so you will be able to fly your drone if it's not-for-profit. And if I remember correctly, drones that fly under a certain altitude (I can't remember what) are considered recreational. Since you have a PPL, I don't think you would be reprimanded for using a drone, as long as you use it like you would fly someone in a Cessna (without charging). Also, this is a new field of aviation that new regulations are being made for, so who know what the FAA will ultimately decide.