I will flag this to Orthidox Presbyterian for a comment..because it seems to me I remember a conversation about Vernon on another thread..If memory serves he had his own theology on this..he believed there were some elect and then there were some that could choose to be elect..I think that theology has a name..But I do not remember..OP might :>)
I am glad you know about Dr. McGee. I found his Bible Studies when I was an "old" Christian - about 12 years after I was made "new" in Christ Jesus! And, then, when I had the privilege of leading a Bible Study Class, his six set volume (along with many other study aids) were invaluable. Dr. McGee's study aids are a TREASURETROVE of information and wit. Dr. Warren Wiersbe's books also helped a great deal in that class. I had to put my own curriculum together, and make my own "handouts" and teaching aids, but our text was the Bible itself.
Do you know who I read early on? Catherine Marshall (Something More and Beyond Ourselves)
She wasn't a theologian either - but her books were inspired. Today, the person who helps me like that is Elizabeth Elliott - whose husband died when a missionary to the Auca INdians and then she went to minister to them herself and her husband's killer eventually became a believer, a member of the Body of Christ, who told that the Living Word (Jesus) gave him a "heart washing" (I think that was the term). Jesus is able to do that for whosoever turns to Him in faith - responding as the Auca Indian man did - confirming that he or she is among God's elect!
In between Catherine Marshall and Elizabeth Elliott, I encountered Dr. Francis Schaeffer. And lately, I am really enjoying the teaching of Ravi Zacharias and also Dr. Erwin Lutzer of Moody Memorial Church - both of whom help greatly, as did Dr. Schaeffer, in thinking about the Christian worldview, and Jesus Christ's claims, in light of the world's "religions."