The Mill Creek trail begins at the trailhead parking area's northeast corner. (See directions below.) Follow the wide dirt route east, disregarding any trails that split off to the left toward the creek.
Arrive at the base of a tiny waterfall at the site of an ancient power station after climbing about 800-ft. Bypass the falls on the right (south), climbing over the cement block dam on a slick rock ledge and then walking along a narrow slickrock shelf beside the creek. The traction along the angled shelf may be an issue for some. If that's the case, go for a swim in the creek. Off Highway 74 is an undulating, high desert trail with an elevation of around 4,000 feet. Pinyon Flats Campground is marked by a sign. Parking in the campsite costs a day use or overnight ticket, otherwise you can park along Pinyon Drive for free. The trail continues west, passing through Palm Canyon Drive.