Well I took my own advice, this is my 5th season for my bike, soooooo
I finally found the negative cable ground, I am going to say it is moderately easy to get at with the right tools.
Looking at the clutch side ( right side), in fact look directly at the clutch lever, look past and you will see the starter, look 3 inches left of the starter and you will see about a 8 gauge black cable bolted to the casting.
Best to remove the trim directly above the clutch, ( one allen head cap screw to remove), you will also need a 10mm long arm or professional box / open end wrench, pair of needle nose pliers. I was surprised to find the casting mating surface was white where the lug was attached, I don't know of any oxide inhibitor that leaves this , so I assume it was oxidized, I scotch brited the surface and put my copper coat inhibitor on it, reattached the negative ground cable and tightened.
If you do alot of riding in the rain or have the bike stored outside, I would look at this connection.