Today I came across a book dedication to Twain that I was surprised
to find.  This appears as the dedication in Bessie and Marie Van
Vorst's book, The Woman Who Toils, Being the Experiences of Two
Gentlewomen as Factory Girls (NY: Doubleday, Page & Co., 1903):

        To Mark Twain
In loving tribute to his genius, and
to his human sympathy, which in
Pathos and Seriousness, as well as
in Mirth and Humour, have made
him kin with the whole world :--
        this book is inscribed by
        Bessie and Marie Van Vorst

There is a Jan. 1, 1902, letter from Marie Van Vorst to SLC listed in
the online database of Clemens letters but I don't know of any other
connection between them.  Does anyone know of any other contact
between them?

It may be that they just thought of Twain as they were working on the
book.  They were well-off society women who pretended to be factory
and mill workers to gain experience of working conditions for women
and children.  They might have thought of themselves as "princesses
and paupers."

Jim Zwick