For a 7:30 gate time I'd allow 30 - 45 mins. The Dolphin bus stops at Swan first, Dolphin second then hits Yacht & Beach Clubs and sometimes Boardwalk. Depending on the season, you probably won't have much competition for seats, but the Boardwalk stop may slow you down.
The stop at Dolphin is slightly downhill to the left of the main enterance as you face away from the hotel. We were very satisfied with the bus service during our Nov. 2002 stay.
Bill From PA