As for transportation, ALMOST everyone speaks English, so its not a problem to get a taxi or use subways. As for the salary, you should ask whether its before or after taxes. I live in mainland China, but I hear that the housing is expensive, so keep that in mind, so I am sure schools are expensive like here in the mainland. Anyway, HK is very cool and expat friendly, and kinda of a nice place to hang your hat for a few yrs.
Cheers