Coastal trekking is not as popular in India as it should be. Not very takers for walking along with the huge coastal line India offers. No one has explored much in this erena except trekking in Goa which is reduced to walking from one beach to another but a serious route has yet to be established.
I suggest to hardcore trekkers to explore this scenic land starting from North Goa to South Goa. North Goa does not have plam trees and most of the time you will be walking under Sun- so start early if you do not like a Sun tanned skin.
Same situation is in Kerala – not much takers for coastal trekking which could have been a boon for looking deep into village lives of people living at coast.