Laura,
The PCP (I call it the Build Process CP)is something I sit down with the 1) project manager, 2) plant manager, 3) quality guy (me), 4) other ket personnel as necessary. You want everyone there who has a stake in the process (don't forget purchasing).
I facilitate it(otherwise nothing gets done). We walk through the build process and try to jot down all key events, key characteristics, safety requirements, environmental stuff, long lead purchase/fab items (both in-house and outsourced), R&M stuff, reviews as necessary, production status meetings (can be the same as reviews), inspection events, shipping/delivery, etc.
It looks much like the project manager's timeline (Microsoft Project)if you look at the line items only. The difference is that you do the breakdown columns on tolerance/spec, eval tech, control method, and action plan (this is a biggy, the auditor always looks for it).
If you have "product families", just develop a CP for the family and then use it (change the header info), adding to it if anything changed. I have a typical "Build Process CP" that can be used to start off any customized build project. Saves me time.
The trick is to get the right people to sit down with you, limit the interruptions, and to be sure no important events are left out.
Hope this helps.