Here is what I gleaned from WTS sources:
*** g85 6/8 p. 25 Gilead Missionary School—‘Making Our Steps Ready’ ***
The training, of course, is designed specifically with this in mind. The curriculum includes (1) four Scripture study courses covering the entire Bible, chapter by chapter, (2) a course entitled Theocratic Organization, and (3) a course called Missionary Service.
*** g83 11/8 pp. 21-22 Gilead—The School Students Love! ***
There are five basic courses: Hebrew Scriptures, Greek Scriptures, Theocratic Organization, Foundations of Bible History, and Missionary Service. "The courses on the Hebrew and Greek Scriptures give basic coverage of each book of the Bible," says Redford. "Foundations of Bible History covers the history of religion and background world history that will help students to understand Bible prophecy. Theocratic Organization traces the history of God’s organization from its beginnings in ancient times until now. Missionary Service deals with the common problems that missionaries have in living in a foreign country."
*** yb71 pp. 59-60 1971 Yearbook of Jehovah’s Witnesses ***
The courses are:
Hebrew and Greek Scriptures: A verse-by-verse discussion, considering the purpose and objective of each Bible book and its meaning and application to those to whom the writings were addressed in ancient times as well as to the modern-day Christian congregation. Documented reports are presented by students assigned to certain Bible chapters, enabling the entire class to note explanations and references on the pages of their Bibles. The Watchtower and other Society publications are the chief reference sources. During the study of the books of Exodus through Deuteronomy there is a classroom presentation of legal cases based on the Mosaic law, with some students acting as litigants and others as judges of the cases. This course covering the Bible runs through the entire five months of the school term.
Doctrines: A course occupying one quarter (five weeks) of the term. This consists of a study of some of the basic Bible doctrines. The book "Things in Which It Is Impossible for God to Lie" is extensively used, as it covers the basic Bible teachings. This book is supplemented by Life Everlasting—in Freedom of the Sons of God, "Then Is Finished the Mystery of God," "Babylon the Great Has Fallen!" God’s Kingdom Rules! and The Watchtower, to which the students are referred for research. Various methods are employed, including reports by the students, open discussion, panel presentations, and so forth.
Foundations of Bible History: A five-week course entailing a study of the history of mankind as outlined in the Bible, with special reference to the nation of Israel and the Christian congregation. Also, considerable attention is given to the ancient nations surrounding Israel and the development of the world powers of Bible history and prophecy. In this course the book Aid to Bible Understanding supplies much material.
Ministerial Activities (five weeks) considers the history of the Watch Tower Bible and Tract Society and the modern witnesses of Jehovah. The activity of Jehovah’s witnesses as ministers under the Society’s direction is discussed and demonstrated.
Language: Languages are taught according to the need, that is, according to the countries to which the missionaries are to be sent. The language course runs through the entire twenty weeks of the term. During the forty-eighth class three separate groups were taught Spanish, French and Korean. One group, scheduled to return to their own countries for missionary work in untouched territories, was taught a special course in "World History," which was an expanded course that supplemented "Foundations of Bible History." The forty-ninth class is studying Spanish, French and Portuguese.