Thank you all again for your help with this!
I've heeded your advice acquired the back-up battery and modern 7.5A fuse holders (as well as a dizzying array of other baubles, 80% of which I surely won't need...).
I've also made plans to upgrade lighting (two white driving lights on cylinder protection bars, running lights all around, red lenses on turn signals in rear, brake light flasher unit, 4-way flash), do a bunch more maintenance in the coming days (spline lube, tune carbs chief among them). I've planned the first few days so I'm never far from home base, or from the houses of friends who can serve as a base, given I'm making a lot of changes.
I recently went over all major electrical connections in the bike, cleaned and dielectric greased them, as well as testing the diode board (was fine) and checking alternator brushes.
I'll make a separate post about lighting upgrades and how I've chosen to go about that.
Until next,
Matt