The published books seem to be only the Newfoundland Songs (and editing the Sharp English Folk Songs from the Southern Appalachians).

However in the introduction to the 1951 edition of EFSfSA she starts off with "In the Summer of 1951, with the assistance of the Library of Congress, I spent three-and-a-half weeks in the mountains of Virginia, North Carolina, and Tennessee, accompanied by Mrs. Sidney Robertson Cowell. With a tape-recording machine lent by the Library we recorded ninety-one songs and instrumental tunes, of which sixty-nine were from singers who had previously sung to Cecil Sharp of from near relations of these singer".
The notes to record The Doc Watson Family Tradition quote the following:

" ""Thus, a song originating in England and carried to America, lives there by oral tradition for some hundreds of years; it is written down and taken back to England by Cecil Sharp; then some thirty years later the song is carried back in printed form to the country of its adoption and takes on a new lease of life. Such are the devious ways of tradition.""

-Maud Karpeles

With these words, Maud Karpeles reflected on the erosion of oral tradition in the Southern Appalachians where she collected in 1951, revisiting sixty-nine families and individuals whom Sharp had first met between 1916 and 1918. In the ensuing years, many of these singers of Virginia, North Carolina and Tennessee had forgotten their own songs and were delighted to relearn them from the publicised transcriptions which she and Sharp had made thirty years earlier."

(The Karpeles' quote is from the same introduction, the commentary is by Ralph Rinzler, Smithsonian Institution, 1977)

The Library of Congress site might be a good place to look next since they appeared to have sponsored the trip. (If I have some time over the weekend I might have a look myself!).

Mick