From Mayflower Spring the trail heads north and then turns to the east and joins up again with the old railroad bed. It crosses FR 132 and then just south of Railroad Tank the trail turns to the east and works its way over to FR 651, which is the entry to Pinegrove Campground. It crosses Highway 3 and climbs up past the Horse Lake Trailhead. It turns to the north and crosses Anderson Mesa, and then passes Horse Lake. It follows a two-track, turns to the west, and becomes a trail again. After crossing FR 129 the trail passes Vail Lake and Prime Lake, and then skirts around the Lowell Observatory. It passes by a trailhead near the observatory, then heads north and then west to Marshall Lake.Southern Trailhead
From Flagstaff, take the Lake Mary Road exit (339) off I-17 for ~20 miles, then turn right (west) on Mormon Lake Road (Highway 90). Follow this about 3 miles to an unmarked turnoff on the right. This two-track dirt road leads to Mayflower Spring (~0.4 miles).Northern Trailhead
Marshall Lake Trailhead
From Flagstaff, take the Lake Mary Road exit (339) off I-17 for 9 miles, then turn left (east) on FR 128 at the sign for Marshall Lake. Pass the observatory turnoff, then at 2.2 miles turn left before Marshall Lake (more of a marsh) and park at the AZT sign on the left. If you are coming from the south on Lake Mary Road, the Marshall Lake turnoff is 7.5 miles north of Pine Grove Campground.