Apparently, Emily Dickinson's trove of envelop draft poems have been recovered, published and on view at several museums, one of which is in NYC.
The Drawing Center
35 Wooster Street
New York, NY
Amazingly, the Dickinson/Walser pencil sketch book is on line to read (with good eyes) and view. The Drawing Center (located in SoHo) is also selling the book for $20.00 plus postage.