When organising (I use that term super loosely!) a hike, I wanted to be able to see how many kilometres it was going to be. The tool I use to use when I would travel and map a possible jog / run I would use Map My Run, so I resurrected my account to map the hike from Malabar to Watsons Bay. Part of it will overlap the Bondi to Manly walk.
Create Routes or Search for a route from millions at MapMyRun
I'm sure there are web and normal apps that allow for hiking path drawing to follow but it's funny how the mind just wants a simple option and has a "go to".