BEVERLY CHAPMAN, 44, a nationally-known advocate of rights for the disabled, died in her sleep early Saturday. Chapman, who grew up in Cape Cod, suffered from a severe form of muscular dystrophy. Cause of death had not been determined. Over the past 20 years, Chapman became nationally known as an advocate for better access for the disabled. The weekly column she wrote for the Orlando Sentinel was distributed nationally. She perhaps was best known for a 1986 protest in which she drove through the toll gates on an Orlando expressway without paying to call attention to the difficulty disabled people had using toll baskets. The Florida Legislature later passed the Beverly Chapman Act, which allowed the disabled to pay tolls in advance and be waved through. In 1989, Chapman was named Disabled American of the Year by President Bush. Recently, she had interviewed for various advocacy positions in the Clinton administration.