For early morning character breakfasts, we are always out at the bus stop an hour before our adr time. The buses start running at 6:15 am, but they are infrequent and unpredictable in the early morning. So you don't know exactly when a bus will come & you also have to allow for extra travel time because you may have to take the monorail from MK to the Poly (sometimes the bus driver will take you directly to the Poly but you never know). I would also allow about an hour for your meal, although most of the time we are done in about 45 minutes for character breakfasts. Not sure which park you will be going to afterwards (I'm assuming MK) - if so, then you will be there right around rope drop or a little before since it's a short monorail ride from the Poly to MK.