Since Super GT ended its season finale just hours ago and the forum's done gone and died (y'all), may as well present my newest finding. There is a ton of land to the north and west of the Twin Ring that's going unused. So, where this is going is obvious. Extend the circuit out to GP length, circuit may be extended out to the hillside to the west (overlooking the road), and, if necessary, up to the river to the north (preferable to minimally use it as Honda certainly doesn't own that land right now).
I'll get one of my own out soon. (probably)