Many of the walks along the Cornwall coast use (or used) Western Greyhound buses to get back to the start point. However sadly the company has ceased trading as of today and so will no longer be running their bus routes. The company did an excellent job in my view when they started, running new services and good connections making it much easier to access the cost path. Sadly they have been in decline for some years and the remains of the company was sold a few months back.
This does mean the links to their bus timetables I have provided no longer work. The good news is Cornwall County Council have already arranged replacement services for most of the routes, where there is not already an alternative and details can be found here.