thoughts about car battery keep hooked up OR disconnect ?

There is no doubt that as old as these girls are, disconnecting the batt for extended periods is not a bad idea.

The original systems are WAY under-fused, and anyone thinking the fuse link is "protection" is fooling themselves. A good example of "how simple" it can be was already given by the horn example. Inside the alternator is a bypass cap. That is hot at all times. If that cap shorts, you might have "interesting."

"If I live long enough" the battery is headed for the trunk, with a "push off" button from the outside. I intend to use a slip-fit tube and rod so that you push the knob to disconnect, but if someone pulls it back out, it simply slips. Open the trunk to turn back on.