The Climber’s Loop Trail in Mission Gorge climbs steeply from the main gorge road up to a popular rock climbing area then loops back down to the road. The rugged one mile loop offers great views and some fun scrambling near the cliffs. The trailhead is located a mile or so past the park visitor’s center, which offers an online map that will help you find the loop. There’s limited parking at the trailhead, so consider parking at the visitor’s center on busy weekends.
If you’re looking to climb here, there’s more info on the crag available from the San Diego County Climbing Guide. If you’re just hiking, mind the climbers. The ones on the ground have someone’s life in their hands. The one’s in the air can knock rocks loose. Rocks are hard.