You can get out there as early as 7:00 A.M. (I was told the first run starts around 6:45 A.M.) but at that time the BWV is the last of 5 stops. (Swan, Dolphin, YC, BC and BW). If the bus gets filled, it will never make it as far as the BW. It changes to a Swan, Dolphin, BW bus at around 7:30 A.M. You may want to walk across the bridge to the Swan and catch the first bus at 7:00 A.M. That way you will at least get a seat and actually get a bus.
They did have a CM at the BWV bus stop each morning of my last trip helping guests with transportation.
HBC