The three distances make this a fun event on the edge of the Northern Beaches.
It's a scenic start and finish area on the shores of the Manly Dam. If the weather's hot, runners jump into the dam for a dip. The longer course offers harbour views.

Check website for ticket sales set to start in December 2017. There's plenty of parking in nearby streets if you get to the venue early enough. 

http://www.sydneytrailseries.com.au/sydneytrailseries/entry-fees