If you have to be there by 7:00-7:15, then you are pushing it. Are you in a power cat or sailboat? We've done Nanny Cay at that time in the morning. But, I'm guessing you're looking at ~ 8 nautical miles. You might want to spend the night at an outer mooring ball (Bight). Maneuvering through the mooring field can be a challenge in nautical twilight. It can also hurt your popularity with those sleeping on other boats.