Thanks, Hayo;
I appreciate the obvious time you took to reply. You've been an immense help. I've just three questions, then I'm going to start getting this workflow set up and running.
By the way; I should note that I did "stumble upon" an article that talked about using ACR to convert JPGs to DNG. It noted that one should use the "linear" option. I tried it and things looked quite reasonable, in fact it seemed to give me more leeway in adjustments.
QUESTION: Is the "linear" option (rather than compressed") what you use?
So; the 10,000 foot view of the workflow is to use PM to ingest the un-geocoded RAW and JPGs (sending a copy to the archive drive), use Adobe RAW Converter (or ACR) to turn RAW files into DNGs and use ACR to turn JPGs into DNGs, geocode the DNGs, then process both with ACR and finally export as 16-bit TIF. From there one can put out any format needed for the web, prints etc.
QUESTION: Is this a fair description of what you were thinking?
I believe that we did discuss processing legacy image files before, but the result may change based on the current discussion about DNGs. I have a script that uses ExifTool to set the capture date/time to the date taken date/time, remove any XMP, IPTC and GPS segments, and remove Artist and TimeZone. The net effect is to return an annotated Canon RAW or JPG to it's original State. I've done several tests and it seems to work well. However; I've also done tests on the RAW to DNG Converter and ACR. They don't seem to care about the precise structure of the RAW and/or JPG data input. They seem to copy the actual image into their own structure and mine the input file for the rest of the data to fill out their own tags. In effect, you get the original image and preview encapsulated in a new metadata framework. (I did notice that they may need to convert the GPS coordinates into their own format and this can result in an infinitesimal rounding in the hundredth of a second. Not something to worry about). So; it would seem that stripping the input files and then re-introducing the metadata would be a waste of time and could be more of a risk than just converting the legacy files "as is".
QUESTION: What do you think about just saving a copy, then ingesting them as they are?