In message .com, Paul
Weaver writes
1) Drive something like Hammersmith, M4, M25, M23, LGW

Additional 20 miles over the direct route. Besides Hammersmith, A4,
A316, M3, M25 would be faster I'd imagine, or the A3 (which is the
route viamichlin says for quickest trip)

I'm a London (black cab) driver, living in Worthing and often travel
home via Gatwick

Try the following (fill in the gaps)
NW3
Baker St (top end)
Westway
Shepherds Bush
Hammersmith Bridge
Roehampton
A3
Chessington (avoids a long detour via A3)
M25
M23
Gatwick

However if you type your query into google maps:
http://google.co.uk/maps?q=nw3+to+LG...1.915192&hl=en

Via Park Lane, Balham and the A23 - no congestion charge


--
Mike Hughes
A Taxi driver licensed for London and Brighton
at home in Tarring, West Sussex, England