Recently I've started work on a couple of long-term projects, in addition to the book on the cross. One of them is a more organized version of MSLN than is on this blog, and of whatever other doctrines I feel should go with it. (Strictly speaking MSLN isn't about epistemology, or is somewhat indirectly about it if it is, but I might put epistemology in there.)
The other is a commentary on the Bible, which I expect to take a long time. The book is about the range of possible ways to understand God and what he prefers, and which ways we should prefer, act, and trust, given that range, for ethical purposes. Also, since I will be reading the Bible, I will see how well the philosophical part of MSLN (MSL, one might say) interfaces with it. (Basically, trying to apply the epistemology of love / altruism to the Bible, given the degree of epistemic and maybe therefore normative uncertainty involved.)
The two purposes of this text are: first, to provide information to any secular people who might have come through MSL to the point of trusting the Bible for ethical purposes (to see specifically how to come into tune with God). Second, to demonstrate the method of uncertainty filtered through ethics ("uncertain obedience") to recommend it to Christians to provide a way to settle doctrinal positions while still acknowledging what we don't know -- maybe this would help to some extent with significant church divisions like that between more conservative and more liberal / progressive Christians.
Currently, with the first, philosophy project, I've read some of Copleston's A History of Medieval Philosophy. Also I've ordered the books in the Wadsworth Philosophers Series on Plato and Aristotle. I found that after reading their book on Berkeley, and thinking about Berkeleianism for a while, when I got to Berkeley's Principles of Human Knowledge, there wasn't a lot new I needed to understand. The titles in the series are written by different authors and are probably hit or miss, and Berkeley may be a particularly easy philosopher to summarize, but I'm still somewhat optimistic that I can get low-hanging fruit out of them without (as) much reading. Also I checked out a book on metaphysics from the library.
I tend to do better by learning the basics of other philosophers' views and then re-deriving whatever follows (that I feel the need to think of), and then maybe looking at the details of what they say. I'm not really interested in being able to, say, accurately explain some other philosopher's work, but I do want to let them influence my own. I also find it useful to keep my mind in the area of philosophy by reading even about philosophers whose views don't interest me.
I don't intend to directly cite very much of this reading in my own book on my own philosophy, which is why I'm okay reading library books.
With the second, Bible reading, project, I have done some planning and drafted some introductory sections and have read about halfway through Genesis in the first pass of reading through the Bible (out of maybe four or five passes total).