This trail is the longest and steepest sustained vertical descent in the McCoy Flats Trailhead area.
Head out of the east parking lot and take a left. The trail will meander for a few miles on the And Cookies
trail. Eventually, you'll come to a fork with a well-placed sign. Follow the sign and go right at the fork. This is where the climb begins. From here on out the climb is fairly consistent. It's not too bad and there are no real technical challenges along the way.
At about 3/4th of the way from the top, you'll come to another fork. This is where the Serendipity Trail
drops off. You'll take a left at this fork and continue on the climb.
Once at the top you'll come to a faded doubletrack. It looks as if you can take a left and continue of the ridge to the prominence. But you'll want to take a right onto the doubletrack. This is the start of the descent. The next couple of miles are relatively steep, loose, and fast. You'll drop into and out of a couple of washes with slight climbs back out, but, for the most part, the trail is a fun descent.
You'll eventually come to a trail intersection in one of these washes. This is where you meet back up to the serendipity trail. It continues through the wash, but you'll want to once again follow the signs and go straight through the wash and make the slight climb back up out. From here you'll be on top of a small plateau the trail continues in a nice winding manner along this plateau for a little while.
Once you come to the edge of the plateau you'll see the trail as it dips off on a short steep descent. This is the most technical part of the whole trail with a couple of small ledges a steep drop. It is nothing too challenging though and it only last for about 50 ft so it's not a long ways to walk if needed. From here the rest of the trail winds through similar to the beginning with short climbs and descents until you come back to the parking lot.