Bombay is the only city in India where I can get in to a Auto outside (in the Auto stand Q with a cop near by) the International terminal and pay meter (Rs 35) or so to Vileparle/Andheri Train station . I get in to a Train and reach chatrapati Station (CST)to catch a night train to Hyderabad.Many times I fly in to Bombay domestic from Chennai/Bangalore /Hyderabad to catch a International flight ( I fly light- only hand carry even to International flight) Mumbai-HongKong direct by Kingfisher & Jet are quite convenient and cheap.If I have less than 3 hours transit time, I get in to the free bus from domestic to International . If more time on hand I take an auto Andheri/vileparle station from the airport. Eat a nice Gujarathi Thali, catch a movie sometimes . With so much traffic jam ,Auto to the nearest station and travelling by train is the fastest option even though crowd and sweating has to be taken in to account.