I am staying at Dockside right now as it happens, having stayed at Surfside on a prior trip. My recollection is that the buses get going one hour before Early Park Admission. So if IOA starts early admission at 7:00am, that should mean the first bus will show up at Dockside at 6:00am. As I have never actually done this however, perhaps an EPA enthusiast would like to chime in with firsthand experience.