This should be my final post on this thread. I have resolved my problem.
What it was not:
It was not a MicroSD Card Format issue. I tried various options, formatting in or out of the phone, transferring files directly to the phone via USB, or to the card directly in a card reader. No change.
It did not require a Factory Reset to fix. I always prefer to find the specific problem if possible, rather than to take a bulldozer approach. Kind of like the advice given from Tech Support for computer problems: rather than taking their time to pinpoint the problem, they'll tell you to reformat your Hard Drive.
The presence of 20,000 Jpegs on the MicroSD card. These are still there, and my battery usage is much better.
What it was:
Media occupied a higher percentage of battery usage because of the presence of more than a dozen movies (avi, mk4 and mp4 formats). Once these were deleted, Media ceased dominating battery usage through the day. Media is high when I first start the phone, as it has to inventory the MicroSD card, with those 20,000 photos, but this drifts down as the day goes on to reasonable levels.
I didn't determine whether it was a particular file, or a particular file format, the number and size of the movies, etc. I can figure that out down the road if/when I need to put some movies back on there. I generally use an Asus tablet for this anyway.
Once Media was tamed, Android System took over. I'm not sure exactly which of these things did the trick, but doing this resolved the problem for me:
Deleted a Nightclock App: I don't know what the deal was here, but this, and Clock, were eating up a lot of battery.
Tweaked some settings in my Elecont Weather App, to check location and weather less frequently.
Changed Google Location settings to "GPS only."
I also turned off some bloatware, but don't think this was a major factor.
The bottom line is that I get the battery performance from my Note 3 that I think I should. It has been stable for several days now. For example, yesterday I had:
14 hours, 40 minutes on battery, with 32% left at the end of the day.
This included 1 hour and 20 minutes of Google Maps Navigation (perhaps one of the most demanding on battery, as it uses GPS, Screen, and Data), 2 fairly lengthy phone calls, including Bluetooth use, and 2 1/2 hours of Screen time. Not overly intensive use, but more than average for me.
My battery percentages at the end of the day showed:
Maps 21%
Screen 18%
Android System 14%
Android OS 9%
Media 7%
Voice Calls 7%
So I'm happy with where I am. These stats are by no means record breaking. But on the other hand, I leave WiFi, Bluetooth, GPS, and Data on all the time, for convenience, and don't take any other specific measures to extend battery life.
Hopefully this thread will be of use to others down the road. Appreciate the help here.
Don