Could use numpad to switch to a city in a particular direction. But to get to all cities that way in a sensible order, you'd have to memorize a sequence of key presses, e.g. starting in capital, go NW (key 9 edit: 7), then east twice (key 6) etc. So not really an aswer to the question posed; thought I'd mention it anyway because it's a rather obscure key mapping.