Just some quick questions. Perhaps a bit

--perhaps not!
How do you all see the use of commentaries and other human writings like Bible surveys, introductions and texts on hermeneutics fitting into this discussion?
One of the gifts of the Lord to his church are what the Reformed tradition calls the "doctors." Eph. 4 says that the Lord will give his church what is helpful to its edification. Do we need extra-biblical aids to be saved? Of course not. But, we don't necessarily need a pastor to facilitate that either. Yet, nobody would argue that a pastor was not invaluable to the church just because one can conceive of salvation without pastoral agency. Commentaries and other scholarly aids can be of tremendous value in study even though they are not "necessary" for salvation.
in my opinion, part of the problem we experience relates to the trend towards untethered scholarship. When scholars are accountable to nobody, are rewarded for coming up with de novo ideas that contradict the Christian message, etc., then their work is less than helpful. That does not, however, mitigate the value of tools; it merely points out the need for discernment in selecting and using them.
For my 33 years of ministry, I have used my Greek NT (or Hebrew OT) and a goodly collection of reference books for preparing sermons and Bible studies. Even in my current retirement home ministry, this morning found me pouring over the exegesis of Galatians 1 for a series I am beginning tomorrow. Could I teach the class with just my Bible (and Powerpoint of course

)? Sure. But, why cut myself off from the exegetical, linguistic, historical, and theological riches of the giants who have gone before me?
Can we just pick up the Bible and "read it like any other book" (something I've heard somewhere in the past) and know what it means? What is meant by the perspiscuity of Scripture?
What do you mean by "know"? Insofar as the Lord has inscripturated his word in human words, the words of the Bible are governed by the same rules of grammar and syntax as any other book. A good translation and the use of ordinary means will yield up the essential meaning. "Perspicuity" refers to the fact the the central message is clear and accessible to a person without the mediation of popes and priests. However, "knowing" is not a simple matter. What we "know" has a lot to do with the presuppositions we bring to the enterprise. A carnal mind blindled by sin will not discern spiritual truths. Since we are dead in sin, only the work of the Holy Spirit can open our eyes, give us the gift of faith, and effect the work of God's grace within us (that is one reason why I'm a Calvinist, not an Arminian).
Is there a difference (or should there be a distinction) between understanding the "essential clarity" of Scripture and the view that "Every part is equally clear." ?
Yes, every part is not equally clear. Some parts deal with milk, other parts are meat. Peter saw some of Paul's writings to be more difficult.
What are the views here on the matter of "the principle of private interpretation"?
Private interpretation was never intended to mean autonomous interpretation, errant interpretation, or heretical interpretation. In this sense private interpretation violates 2 Peter 12:20-21. What was meant by the Reformers was a rejection of the Roman Catholic magisterium in favor of sola scriptura. Scripture applied by the Holy Spirit, not tradition, rules.
How does our appealing to the views of the Reformers, the Puritans, and other Bible scholars differ from the Roman Catholic practice of appealing to tradition?
If I cite Calvin with approval for my interpretation, I am doing exactly what the Roman Catholic scholar does when he cites St. Thomas. However, what the Roman church means by tradition includes more than this. With Trent, tradition becomes a source of authority equal to the Bible. While some on this board may want to invest Calvin with incredible prescience and wisdom, none of us would say that Calvin is an equal authority to the Word of God.