There are manuscript collections that I read about that I wish I could take a 6 month break and just go read and soak in the information.
Women, Enterprise & Society from Harvard Business School is one of those collections. According to the website "This Web-based publication identifies materials in the Business Manuscripts Collection at Baker Library that document women's participation in American business and culture from the eighteenth through the twentieth century." But you get a sense of the richness of this resource and how it can help a family historian by reading the descriptions of some of the collections.
Afro-American Agricultural Laborers Collection
Mss 1 1797-1799 N892
Includes payments to women for spinning yarn.
Allen-Lane Company Collection
Mss 761 1853-1941
Includes payrolls of nineteenth- and twentieth-century New England textile mills, as well as stockholder records, family records, and information on knitting outwork.
Boston Manufacturing Company Collection
Mss 442 1813-1930
Payrolls of a nineteenth-century Waltham, Massachusetts, textile manufacturer include employee records for women workers.
Isaac G. Pierson and Brothers Collection
Mss 501 1795-1865
Records of nineteenth-century nail and cotton factories include employee records for women workers and company store records.
Roxbury Carpet Company Collection
Mss 461 1837-1923
Labor records of nineteenth-century Massachusetts carpet and textile factory that employed mostly women workers.
There's much more to this collection and website. I recommend you read more about the project via the Introduction page. The website has a great bibliography you'll also want to check out.