It does not seem a very good route?
https://maps.google.co.uk/maps/ms?ie=UTF8&t=m&vpsrc=6&oe=UTF8&msa=0&msid=211183794269622219925.0004ad3cc8ae65b80645a
I was think of cycling from Shoreham as the trains are so bad. I like to get off busy main roads.