Mark Twain did attend numerous dinners at the Garrick Club. He
discussed these in his book MARK TWAIN IN ERUPTION, p. 331-333.

An early visit was in July 1873 at a dinner hosted by Anthony
Trollope.  A lengthy annotation about that event is online in his
letter to Mary Mason Fairbanks.

See:

http://tinyurl.com/3fmaxdq

Joaquin Miller also wrote about this dinner in 1882.  His article is
online in the New York Times archives at:

http://tinyurl.com/4x45lvo

Barb