One thing that I have come to recognize is that this book actually follows the format of the Judeo-Christian bible. If you map how the styles of various chapters proceed, it follows a remarkably similar progression to the Bible, right down to the musical, poetic, and proverbial books of the Old Testament. Not only that, but more diligent scholars will notice that it includes many archetypes and myths of Judaic culture, carefully woven into the story. Except that the stories have been rewritten with an ethos and moral sense that a Thomas Jefferson or Ben Franklin could identify with. In fact, it has a very explicit American cultural context. My belief is that Heinlein was writing a theological epic, modeled on the Judeo-Christian theological epic, but replacing the Hebrew cultural elements and religious law with what he believed to be the fundamentally American principles of morality and ethics, and following the logical consequences of this premise in a Judaic mythological framework. In a sense, it is a complete, thorough, and well-thought out theological epic in its own right, comparable to the theological epics of many other religions (except better written and more accessible).
And yes, Lazarus Long is a man to aspire to in that book and a hell of a character. The embodiment of wisdom and experience; I wish I knew people like him. But yeah, "Time Enough For Love" is one of my all-time favorites. A collection of parables, proverbs, and epic histories that happen around the life of an otherwise ordinary man born in the early 20th century who somehow lives for thousands of years, as seen through the eyes of his future historians. Simply classic in my opinion.