I cannot stress how useless Balance's Retreat is. You'd have to import food for the entire area: the Retreat, the mountains, all of it. There isn't enough gold to build a realm or maintain an army. Because it's so useless, it's actually much more useful as a kind of perpetual monster preserve, where realms can go hunting and advies can always have work. IC, that's exactly what it is: the hunting range of House Solari, shared with his good friend Busto.
Well there is that too, but maybe someone could set up a hunting lodge in BR
