There are very good ideas here. To recap, there are at least three sets of commentaries that you might use, depending on your budget and time, etc.
You might find a good group study in your local parish, but you are captive to the leader and the attendees. I’m just saying you might like to study on your own, rather than depend on the group.
So, there’s the Navarre commentary, probably the most expensive. The Ignatius series is probably the cheapest.
I’m working through a set of commentaries that I find very helpful to me – they’re non-academic in style, suitable for individual or group discussion. Four volumes of 14 have been published so far in this Baker Academic Catholic Scripture Study series.
Yeah, the standard advice is to start with the New Testament, one of the gospels. But, you can start anywhere you want. In the Baker Series, the study on Ephesians is excellent and inspirational – and a stand-alone commentary, so everything is in there to get you through this one NT epistle. The author does not leave anything to the imagination so you won’t miss anything in the letter. You’d need a much more scholarly book to get much more than you can get out of this book.
IF you pick up the Ignatius Bible study book on the gospel of Mark, if I’m not mistaken, you will get a good lesson in the method of Catholic Bible study, as it contains useful and revealing information from the Catechism and from various documents of the Second Vatican Council.
I made a plan in 2009 to read through some Jewish commentaries on the Torah, the first five books of the Bible. There are five books listing at $75 each (I caught them on sale for $40 each) and there’s nothing forbidden about reading these, except to realize that they’re not from a Catholic perspective. But, they do provide a lot of line-by-line explanation of the Hebrew text. I only made it through 3.5 of these five books, because I got distracted by other reading. Realize that the Jews read the Torah at Synagogue on a three-year cycle. They are focused on all the commands and inspiration of these writings and all the Hebrew scriptures. On the other hand, they are lacking the Christian perspective and they don’t hit all the issues even in these books, as extensive as they are.
From the EWTN document library, you can download a document from the Pontifical Biblical Commission about the Interpretation of the Bible in the Catholic Church. It’s heavy reading, but if you don’t let it overwhelm you, what you find is that it tells different methods of looking at scripture, and the upside and downside of each of the methods.
To make a long story short from that document, it says a Catholic should get a good commentary to read alongside their Bible.