Pinjarra has a large Grassy area big enough for any size rig. It's between the Heritage Railway station and the road. Although you hear both cars and trains during the day we didn't hear them at night.
A ranger comes by to check your rego and I assume to make sure you look self-contained. They were very nice and it's good to know they are keeping an eye on the place.
You can use the dump point located on the road, opposite the Pub. Many vans stop and use it as they pass by.
Although toilets are at the train station you have to be self-contained.
A playground is also at the far end of the camp near the toilets.