[shorod]

While knowing the fuel pressure is not a bad thing, it definitely sounds like you need to focus your current attention on the charging system/battery like your plan.

When trying to start the engine after a trip to the grocery store did you get a single click when trying to start the engine, a click followed by a rapid series of clicks, or no sound at all?

A single click would suggest an issue with the starter assembly. A series of clicks would suggest a drained battery.

-Rod