Like, yeah, there's some sketchy stuff with connecting those loads to this over extension cords snaked all around the house, but this setup is basically what you're asking for.
GP is asking for the non sketchy way, that lets them use their outlets etc. Which is not trivial because if you still want to be connected to the grid you need to make sure you don't feed power back into it when it's not expected, like during a power outage.
Like, yeah, there's some sketchy stuff with connecting those loads to this over extension cords snaked all around the house, but this setup is basically what you're asking for.