I don't understand the concern you are creating for yourself
The inverter charger has to be on during shore power hook up or it won't charge your batteries
Which means if you turn it off, your lights, water pump, fridge controls will use battery power until the batteries are dead
And No you do not want to pre wire some kind of by pass, unless it can be under lock and key and not accidentally turned on to burn up things that should not be cross connected
I second the suggesting of just carrying some wire nuts along
You might need them some day to splice some broken 12v connection, or to help somebody else