The best secondary source is Vol II of the "Crawford Brothers" by Allen W. Scholl. The book has been reprinted and I think I got it off Amazzon. There is one very serious problem in it, however. It asserts that this George Crawford is the son of Valentine Crawford,Jr., the famous Virginia Crawford brother of William Crawford. Some people question that link. However, the information on George Washington Crawford's line "downward" appears well substantiated and includes a 1894 interview with him published in a North Carolina newspaper when he was 93 (there are two George Crawfords, the father born around 1750 and the son, George Washington Crawford, Jr., born in Burke Co. NC in 1801. If you send me an email (just click on my name above), I'll be happy to scan some pages for you.