Chanteyranger, I believe you asked whether the entire collection will ever be published. I don't know but it is a very large undertaking. It comes to 4066 individual performances. Some of those are retakes of the same singer singing the same song. There are also some fiddle tunes. But most, of course, are ballads and other songs.

There are a number of books containing songs from the collection...
Ancient Ballads Traditionally Sung in New England (4 volumes)
A Garland of Green Mountain Song
The New Green Mountain Songster
Vermont Folk Songs and Ballads
Ballads Migrant in New England.

Perhaps Mrs. Flanders' granddaughter, Nancy-Jean, will comment further.