Mission Trails Regional Park is a 5,800-acre open space within San Diego city limits. It is the seventh largest urban park in the United States, despite its size and ease-of-access it is relatively under utilized by runners and hikers during the week, this is besides the ever popular and über-crowded Cowles Mountain Trail, which is pretty much busy 24/7.
Start this run from the Equestrian Center off Mast Blvd, on the border of San Diego and Santee, if you use Google Maps this parking lot is known as the “East Fortuna Staging Area.” You will go straight for less than a mile before turning left at the first possible left. You will then head straight for about half a mile before hanging a right and running on the pedestrian-only asphalt road known as Father Junipero Serra Trail.
The road portion will end soon enough and you will bear right and roll through Old Mission Dam and into Oak Canyon. After a mile through Oak Canyon you will keep right and begin climbing on the North Fortuna Mountain Summit Trail. It will be gradual at first and then gets very steep as you begin ascending the “powerlines” climb named fittingly because you will see powerlines as you are looking up praying to the gods for a motorized zipline or drone to help you reach the top. It will be worth it.
After cresting the top you will begin a gradual descent about a two miles or so through “E-Ticket” and through the rock garden, bottoming out right in view of what is coming next. The “Stairway to Heaven” the steep, rocky, staircase up South Fortuna Mountain that you could do 1,000,000 times and that never gets easier. The top of the staircase will be about mile 6-6.5 into the run. And if you weren’t praying for the drone after the powerlines, You will be now.
The steep climbing is done. You will now climb gradually before a steep descent into the top of the powerlines climb again. You now get to coast, or slide (your preference) down the power lines climb that you were just swearing at 3-miles ago. You are retracing your steps now except at the top of oak canyon you will go straight and then right near the start you will take a left and finish at the upper part of the parking lot where you started.
Totals for the run are 9.34 miles and 2100ft gain.
For a detailed map see this link