I will post the dates and times of my signing tour in the "touring" thread uptopic. Thanks for asking.
As for your other questions (boy, you folks are relentless), I don't have the precise population of King's Landing on the exact area of Westeros immediately on hand.
In very general terms, however... King's Landing is more populous than medieval London or Paris, but not so populous as medieval Constantinople or ancient Rome.
Some readers have likened Westeros to England because they see some general similarities in its shape, and in its location off the west coast of a larger landmass. The latter is true enough (I don't see the former, myself), but Westeros is much much MUCH bigger than Britain. More the size (though not the shape, obviosuly) of South America, I'd say.
The other continent is bigger, Eurasia size.
Yes, a league is three miles.