Ed Sanders has a great essay on “Did Paul’s Theology Develop?” in the Richard Hays festschrift The Word Leaps the Gap where he offers a nice summary of Paul as “human and missionary.”
First, a reminder about Paul himself, whom we have been discussing as a theologian: he was also a human and a missionary. He spent years of his life on the road, carrying (presumably on pack animals) his tent, clothing, and tools – not many scrolls, if any. He carried the Bible safetly tucked away in his head, where it belongs. As an apostle, he often supported himself by plying his trade. He was busy, traveling, working with his hands, winning people for Christ, shepherding or coping with his converts, responding to questions and problems. And he was very human; he knew not only fighting without but also fears within (2 Cor 7:5). Paul the completely confident academic and systematic theologian – sitting at his desk, studying the Bible, working out a system, perfect and consistent in all its parts, unchanging over a period of thirty years, no matter how many new experiences he and his churches had – is an almost inhuman character, either a thinking machine or the fourth person of the Trinity. The real Paul knew anger, joy, depression, triumph, and anguish; he reacted and overreacted, he repented, he apologized, he flattered and cajoled, he rebuked and threatened, he argued this way and that way: he did everything he could think of in order to win some. Naturally his mind matured, his thinking grew.
Sanders also has more on Paul memorizing his Bible in “Paul’s Jewishness” from Paul’s Jewish Matrix, which you can read in its entirety on Google Books.