Thank you all for your input on Wyperfeld.
we camped at Snowdrift camping ground, a great place for free camping, fireplaces, and surprisingly even some firewood cut up and provided by the Ranger. We drove down to Wonga campground through some sandy, but not too challenging tracks ( in dry condition). At Wonga you have to online book and pay to stay, however the campground is fantastically spacious ( ideal for forum group camps hint hint!!). But we only scraped not even a quarter of the park. Will be going back to explore the other side.
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