Gregory's isn't actually in millstream, we take back tracks into it from the tom price access road, but if you go into millstream then go through crossing pool and follow the pipeline for a bit untill about 300m from a gate, turn left and then it's an hour in from there. Probably one of my fovourite spots up here, and not to far from Karratha, depending on which way you go it can take anywhere from 2 - 4 hours to get to it, we left at half 2 last week on the way home and pulled up at 6pm, that included a couple of pics and a flat tyre.