Where you turn off the highway, if you don't take the left to head towards the deck, but rather go "straight" err... hard right, you will understand if u are there and then you more or less keep to the right (down a small steep hill and past some old junk logging equipment) you will continue on to find an old, unused gravel pit. Super fun to crawl around in for any vehicle, and is a great spot for taking pics. Also if you explore the road south of my waypoint "Creek, a bit mu..." (its under the power lines) thats loads of fun but the end of my tag on that is that its a bit much with out a buddy. However you can continue northeast under the powerlines and for some km's and end up in a fantastic fishing spot. Its super fun to explore in there. I havent explored to much further north of the deck yet except to find out that the gates are all closed if you want to exit by britannia beach.
Anyhow, I do think the deck would be a great spot (especially in the summer) for a meet and greet bbq.