The 1890 special veteran census shows Elizabeth as the widow of William A. Curtis of Homestead. William served in Co. I, 2nd PA Calvary 1861-1863 and Co. E, 1st PA Calvary 1864-1865.
Elizabeth received a pension for William's service in the Civil War in 1908. A minor child of William's received a pension in 1891. The numbers are Appl. 896,164 Cert. 829,529 for her and Appl. 524,667 Cert. 464,089 for the minor. This pension file may contain considerable information that is genealogically helpful. Elizabeth had to prove she was married and not just in name only. It might also have info on her birth as well as his. However, it is hard to say how much helpful info it contains. It may be a little or it could be quite a bit.
You can get a copy of the pension from the National Archives in Washington, DC. for $75, however, fold3.com is in the process of scanning the pensions and putting them online. When they will have them all done I don't know and you do have to subscribe to their service.