Thanks Ben, good thoughts. I checked amp draw this morning, as well as the battery and all the pos. side cables. Nothing raised a flag. At idle, a/c set to max, radio on, headlights and driving lights on full draw was 80 amps, at 12.6 volts. Engine idling and everything off 36 amps at 13.6 volts.
No one that I am aware of has pulled any of the six ground straps, but that's something I can check after work tonight. Might have one corroded or coming loose.