I was generously provided material published in the East Orange Gazette
from 1884; advertisements and a review of the show.  I was also provided
with an architectural drawing of the theater, all courtesy of the East
Orange Public Library.  For those of you interested in such things, I'm
including my own transcription of the review:

East Orange Gazette, November 13, 1884
Mark Twain and George W. Cable
A very novel and pleasing entertainment was given in Music Hall on last
Thursday evening, consisting of readings by Messrs. Samuel L. Clemens,
(Mark Twain,) and George W. Cable.  The former is widely known as one of
the great American humorists, and the latter is the author of a number
of stories of Creole life in Louisiana, which, published in the
"Century," have attracted much attention.  The novelty of hearing
authors read their own compositions, together with the celebrity of both
gentlemen, attracted a very large audience.  Mr. Cable was the first to
appear.  He is a small man with a large forehead, and pleasant, animated
manner, and his first selections, which were the rendering of several
Creole songs, were very acceptably received by the audience.  He then
gave a rendition of "Raoul Innerarity," from this book "The
Grandissimes."  He was followed by Mark Twain, whose appearance was
totally different from that of Mr. Cable.  He is a man of considerable
height with a decided stoop to his shoulders.  His head, which is
covered with bushy iron gray hair, is quite large and he speaks with a
peculiar drawl in perfect keeping with the style of his compositions.
After a humorous reference to the political election, Mr. Twain
proceeded to give a "telephone talk," and for an encore gave some of the
difficulties  in learning the German language.  Mr. Cable followed with
another selection from the "Grandissimes" and one from another work
entitle "Dr. Sevier," both of which were highly appreciated.  Mark Twain
then gave readings from some unpublished sheets concerning the famous
Colonel Sellers, whose visionary projects excited the uncontrolled mirth
of the audience.  He also, after bringing the audience into the proper
mood for its reception, told a ghost story, the termination of which was
decidedly startling to the audience.  The entertainment was much enjoyed
by all those present and was very successful financially, as well, the
house being crowded in every part.

PDF of Newspaper Provided by the East Orange Public Library


My Twain Gazetteer entry for this venue is at
http://bscottholmes.com/content/music-hall-orange-new-jersey