How do I go from an AC plug on the inverter, to a breaker box?

[ADDvanced]

For the panels, yes.
In a totally offgrid system (including the generator if any) where a N-G bond is derived in the panel and the output H N G is GFCI protected in some fashion it is unclear to me why a driven-in-dirt ground rod adds any safety to a system that has no circuit potential to the dirt other than after you connect the ground rod. Even outdoors with an older not-double-insulated tool leaking to/through its housing any current will immediately disconnect the GFCI that is present.

With any grid/powerco connection, however, the dirt on the ground always has circuit potential with the grid; you would neither want to connect a “second” ground rod to that system in a non-compliant manner nor establish the bond in a subpanel. I digress.

NEC or not: in an offgrid independent source of power with no circuit interactions to the grid whatsoever I’m not certain ‘earthing’ the system provides any advantages whatsoever.

I’m not being obstinate or whatever but I’ve yet to read any explanation other than lightning that makes sense to me. The panel frames should be independently grounded for lightning but “in my mind” the equipment on the interior is probably immune to lightning due to not having potential with the dirt/earth and the Van De Graf Effect.
I’ll gladly concede should a reasonable explanation of the potential (lightning vulnerability) of a floating circuit be provided but this is the current opinion I have arrived at regarding a dirt/earth connection to an offgrid system.

That's kind of where I'm at right now, to be honest. I grounded my panels/brackets/roof to a ground rod in case of lightning. Interior is ungrounded, but I have been wiring all the outlets with continuous ground in case I want to ground the electrical side of the building at some point in the future.

 

[12VoltInstalls]

have been wiring all the outlets with continuous ground in case I want to ground the electrical side of the building at some point in the future

120-240VAC absolutely should have a ground regardless of one’s opinion about copper stakes driven into the dirt. There ALWAYS needs to be a central N-G bond: that’s entirely and 100% not the same as that bond having an earth/dirt connection to a ground rod.
Further, I’m not even stating it’s specifically harmful to have an earth/dirt ground rod with an entirely offgrid system. I merely wonder if it is necessary. Well necessary outside of meeting ‘code.

When it’s so very easy to do and we know the benefits of the green/bare/ground there is absolutely no excuse or viable reason to not have a properly wired safety ground.

Every system needs to be a grounded system. The only diversion for discussion is the question of a driven earth/dirt ground rod in an offgrid system.