A 4km boardwalk loop leads to the petrified forest (take the trail behind the toilet block; another dirt road to the left leads to private land). The dry season between May and November is the best time to visit, as water levels rise during wet season, covering some of the fossils on the riverbed. These absolutely remarkable large stone trees are between 60 million and 500 million years old; the most colossal of them all has a trunk two meters in diameter trunk and 15 meters long.
Due to the park's location, it gets few visitors, so you'll likely be the only ones there. The petrified forest is a 1.3km walk from the information center; staff will point you in the right direction.