I have completed Sarah Cotton and Thomas Halbert's book and it is in the Library of Congress and the Library for the Daughter of the American Revolution. The book is titled "The Cotton Family of Northern Virginia" Volume 5 - Sarah Cotton and Thomas Halbert Family. It is 560 pages long with 833 allied families.
I truly wish that I had met you two years ago. I am trying to convert more than 35 years of research on the Cotton family and all of their descendents to books for future generations before something happens to the data.
Thomas was born in Virginia and died in Mill Creek in Nelson County. You might want to check the court house for an estate settlement. There also should be a petition for partition when he died so that Sarah could get her dower. There may also be an estate settlement for when Sarah died around 1831. I have next located any graves for then but they were part of the Mill Creek Baptist Church.
Have a great time in Bardstown.