possibly a reference to Carolyn Elizabeth Adams (born May 6, 1946), later known as Mountain Girl and Carolyn Garcia, a former Merry Prankster and the wife of the late Jerry Garcia. As Garth says that they share in everything and don't keep secrets. So was the rekationship between Adams and Garcia. She even recieved writing credit on some of the dead albums.
shareI wondered about too as soon as I heard the name!
shareAnother possible (side) reference:
In "Intolerance" (1916) the Mountain Girl falls in love with Belshazzar, to whom, according to the telling in the Bible, the "writings on the wall" appear, which is referred to by Mrs. Munson in the beginning: "Many, many done tunkalow parzen. You been tried and found wantin'. You don't want that writin' on the wall. Feast of Balthazar."
"tried and found wanting" -> trial and error -> Garth's trial balloons
http://www.imdb.com/title/tt0006864/