Some area businesses are hoping to find their own source of green at Don Carter State Park. “Doing Business With Don Carter State Park,” a free seminar Wednesday at the Hall County Government Center, attracted some 20 potential park vendors and concessionaires at Don Carter, which opened in July off Lake Lanier in North Hall. “Having a state park in our backyard is just a great opportunity,” said Sue Albright of jB Jams, a Gainesville-based event planner and designer, after the meeting.