Thanks for all of the replies and suggestions.

I checked the obvious first, and I discovered that I have heat within a
few minutes of starting cold.  This was the case despite the temp. gauge
barely moving at all.  Once i drive around for a long while (don't have an
accurate estimate yet), the needle rests right over the LED.  Of course, I
don't know if this is inaccurate given its general behavior.  However, on
the couple of occasions when I've idled for a little while or climbed a
long grade, the needle has budged a bit above the LED, and the low speed
of the cooling fan kicked on.

So, though it's only my best guess, all is functioning properly "under the
hood".  It's just the gauge that's off.  In addition, at least a couple of
people pointed out that my report of a fuel gauge not registering full
when full could be consistent with the symptoms of the temp. gauge.  It
only gets to about 3/4, and then goes down at what seems to be a normal
rate.

I haven't explored fixing this problem as I have other parts that more
urgently need to be replaced.

Thanks,
David