Methodology
The scenarios for the origin of the Book of Mormon involve two basic levels of assumptions: either Joseph used the plates or he did not. These can each be broken down into whether Joseph used a curtain or not.
In the table below:
Unshaded scenarios involve divine intervention.
Dark shaded scenarios involve no divine intervention.
Light shaded scenarios involve supernatural intervention of whatever source a person wants to believe.
From Ensign, 1988:
How long did it take Joseph Smith to translate the Book of Mormon? by John W. Welch
How long did it take Joseph Smith to translate the Book of Mormon? by John W. Welch