If you cross over the Great EAstern Hwy you can either follow the highway all the way down to the Hardey Rd traffic lights and then head towards the river via Resolution drive. That road goes past the petrol station and joins onto Garrat Rd, which then leads to the bridge over the river. You will then need to head over the bridge and up the road until you find the first side street you can turn into - to the right. Once you are there head in a couple of streets and turn down towards the river. You will need to check the street signs, there is directions. But, it does not really matter because you will find your way there soon enough. If you are wlaking you could get across by going under Tonkin Hwy bridge and walking on the paths, or by taking the same way I have just explained, but by the river instead of on the highway - that would be much nicer. Of course, if walking, once you are over the bridge you can just head down towards the reserve.