OK, an update on the facts so far--thanks for the suggestions!
Last night I did some fiddling and managed randomly to get power through the car--the dome light came on. When I went to start the car, all that happened was a "click" and everything went dead. I have traced power through to the fuse box. "Shorty" is fine. I did notice that the power is significantly decreased by that point though--a starter issue? I have isolated the battery as not the problem--it's something in line. All visible connections and leads look good, so I'm strongly suspecting a component--starter, volt regulator, generator, or maybe the ignition switch. Either that, or there is a short somewhere. Or maybe an unfortunate combination? I have done a lot of work on this car myself but am by no means an electrical expert...so am literally in the dark with this problem.