The north Quail Creek trail is under construction. At the time of this writing (January 30, 2020) three miles of the route can be done as a 6-mile out-and-back. But it is NOT actually open for riding, so I'm asking you to check in at Over The Edge in Hurricane for permission. Ideally, you could combine your ride with a trail workday. It should be considered an "adventure ride."
A 6.5-mile out-and-back will have 950 vertical feet of climbing. It will be more work than you'd expected.
As the trail meanders around, there will be some spots where a gooseneck brings two sections of trail close to each other. Do not, DO NOT, cut through to make a shortcut. Stay on the official path.
Some of the trail feels "finished" while other bits are quite raw. These are intermixed along the length of the trail. Plush stretches are stuck between unfinished parts that are little more than flag-line. It's unlikely you'll do the whole thing without walking over several "to be fixed later" spots.
At mile 3.5 from parking, the trail dead-ends (January 2020).Take the Highway 9 (Hurricane) exit from I-15. Drive 3 miles east. Turn left on Highway 318 (at the traffic light) toward Quail Creek State Park. Drive north, all the way past the end of the reservoir. Just as you approach the T intersection with Old Highway 91 near the Harrisburg KOA, find a parking spot on your right. Follow the path downhill then east 1/4 mile to a broad area along the creek with a rope-swing. That's the creek crossing. The trail is on the other side.
Track file (from secondary one-car trailhead): Quail North