i didn't see any snakes there but we got mugged by a bunch of Possums. We were told not to feed the animals but we didn't get told that the animals would jump on you and try to wrestle the food from your hands.
I don't remember Snake Lagoon but we did go to Flinders Chase NP. We will never forget the possums in Tasmania at Freycinet NP though. My husband got up in the middle of the night because a possum had got into our garbage bag. The possum bit him really hard on his finger (drawing blood) in the fight over who should get to keep the garbage bag.
We have, as usual, digressed a long way from cycling though........oops
There is a pedestrian or MTB track in Lane Cove NP starting at the bottom of my street. It is not uncommon to see brush turkeys strolling around the street and in and out of neighbours yards. They create nests in people's gardens and insist on not being scared off by people, cats or dogs.