The White Street book you mentioned was written by Paul Kovacs. I believe there is a 2nd edition of the book. All production was done at White Street until they outgrew the facility in 1909.
I've not heard of another stash of Lionel Paper unless it was in the granddaughters possession. Some of the items they had are "out there" but the bulk of it when it was sold, I believe, remains underground. What a shame.