I first heard about this more than 10 years ago from an article in The Smithsonian that identified one of the women spies as a Quaker lady. The Tories took over her house, and he older son had volunteered with the Colonials, despite their Quaker religion.
According to the story in The Smithsonian, she would lie on her bedroom floor at night and listen through a knothole to the British officers gathered around her dining room table. Then she would write the information on a piece of muslin (troop movements) and make a covered button with the cloth and sew it on the clothes of her younger son
The younger son would head to market with his fatherthe following day and take a detour to visit his brother in Washington’s camp where Washinngton would cut the button off of the chil’s clothes and unwrap it an know where the British troops were planning to fight the next day.
The Smithsonian knew herr name, but I’ve forgotten it.