Okay, I've had the chance to do some troubleshooting. Please see my
original post below for background...

With the ignition switch in the ON position, I used a voltmeter to
verify that several fuses under the dash were not getting power. One of
the two ECM circuits, the horn circuit, etc., consistent with the
pattern of things that aren't working and with failure of fusible link
C.

I took out the battery so I could get to the fusible lnks.

The four fusible links come out of a watertight connector and are
spliced to large red wires that disappear into the main wiring harness.
All four of them have "2.0 SQ. MM FUSIBLE LINK" printed on their
insulation and they're sort of light tan. (It's hard to see the color
in the dim light with a flashlight.)

I parted the connector so I could look at the terminals. The spades in
the part on the firewall are all pristine. I checked continuity between
them and the battery cable terminal and they're all good.

The holes surrounding links C and D are both partially melted from heat
and the terminals discolored by the melted plastic.

I took resistance readings from the terminal of link C in the connector
to the fuse box, with the ignition switch in the OFF position.

The left hand column of fuses is a direct connection to fusible link C,
at about .16 Ohms, and again correspond to the circuits that are
effected.

The second column of fuses reads about 4 ohms.

The rest of the fuses are not connected, or at least greater than 200
ohms, which was the scale I was on.

Is that what I'm supposed to see? Which would suggest to me that the
immediate cause of my electrical failure is the CONNECTOR?

Any thoughts as to what should I do now?

Thank you.

Mike D.