Here is the first section after the introduction for my Jonah study:
Author, original audience, and original message.
The time-locked perspective is the author's original message to the original target audience. While we recognize that the Author of all Scripture is God, we also recognize that He used authors to actually write down Scripture and those authors' perspectives and personalities are part of God's inspired Word.
Some books are fairly easy to nail down all three pieces of information; for example, 2 Timothy is a letter of encouragement from Paul to his disciple Timothy. Luke's gospel is a letter to his friend Theophilus that is designed to "write it out for you in consecutive order...so that you may know the exact truth about the things you have been taught." (Luke 1:3b-4).
Other books are not so straightforward. Many great theologians from across the spectrum of time have failed to definitively determine the author of Hebrews; many opinions exist as to who it may have been, but no proof of authorship is conclusive. However, the original target audience (Letter to the Hebrews, so one assumes they were Hebrews...) and original message do not depend on knowing the author.
Also, Moses is said to have written Deuteronomy, and yet that book records his death - not exactly possible without either a ghost writer or a ghost...writer for at least that part of the book. Moses is also the writer of Genesis, which takes place many hundreds of years before his birth. In this case, Moses wrote under the inspiration of God to the "new" nation of Israel about their origins (fun fact: Gen 1-11 address the creation of the world and all the nations; Gen 12-50 address the history of four generations of one family). So the time-locked message must be focused on the time of writing, not necessarily the time described. See also Job.
Sometimes, the author and the target audience can have little bearing on the original message. 2 Timothy comes to mind in this example. Paul, the author, writes to Timothy, the audience. While we can deduce certain things that relate to the time-locked study (Timothy may have been wavering with the threat of persecution from without the church as well as from within), the same things that Paul says to Timothy could have been written to another wavering disciple from another apostle. Of course, this is not to say that some very important points have added weight due to Paul's authorship (one who knew persecution intimately!).