Cleveland your post has me thinking about what I would recommend to someone who "wanted to read a primer on philosophy, thinking that such a background might aid my Epicurean studies."
I haven't read many such primer's myself, and I suppose it would depend on the person and the primer what makes the most sense. If anyone has recommendations of primers that are written from non-Platonist or non-Skeptical or non-Stoic points of view, please comment in this thread.
For some reason something that comes to mind as attempting a basic comparison between Epicurus and others is the Appendix to the DeLacey translation of Philodemus' "On Methods of Inference"
The three chapter headings in the Appendix have been valuable to my understanding of some very basic issues:
- Sources of Epicurean Empiricism
- Development of Epicurean Logic and Methodology
- The Logical Controversies of the Stoics, Epicureans, and Skeptics
These appendices are relatively detailed, and they for me they were almost more valuable than the translation (of which large parts are missing) for understanding some very basic issues. I seem to recall that David Sedley has some different viewpoints from DeLacy on certain issues (can't remember what right now), but I think these appendices are worthy of reading on their own for the background information they provide.