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)
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