@optimusprime: I'm well aware of the factory service manual; I've even provided links to its contents in a few spots. The issue isn't with knowing that it exists, the issue is with knowing what to look for within that manual and where to look for it. I have yet to find OCR'ed copies of the PDFs, so it's difficult to search through them automatically, and the indexes are lacking at best, often taking hours of poring through to find something even tangentially related to a topic when you're a newbie like me. Trust me, the factory service manual is the first place I look, but I often miss parts of it. For instance, the X27 test connector's location was squirreled away in the electrical troubleshooting manual instead of being colocated with all of the other articles related to the starter / ignition system. Often times, people with far more experience than me are going to be able to double check my assumptions, and when they point out I'm wrong on something (as Frank did), I learn.

@slk230red: Thanks for the feedback! I'm certainly starting to suspect the starter - I'm guessing that it will either be the neutral safety switch or the starter. Since I tried starting it while wiggling the shifter around neutral, I'm almost expecting a starter issue.

My mechanic told me that you can sometimes get a starter that's getting ready to die on you to 'wake up' by pounding on it with a dowel. I'll plan on doing that if the jumping the X27 point fails. Either way, if the X27 point fails later today: sounds like I'm replacing the starter.