Could El Monte Rd not correct? I don't think it is El Cajon Mountain (16+ miles away from El Monte Rd) like the one article's title says, but Mission Gorge Climbing, which has a Lunch Rock hiking spot (5.5 miles away from El Monte Rd) that is mentioned in one article.
For those not familiar with this area, Mission Gorge Climbing is really close to a lot of very popular hiking trails- Cowles Mountain and Big Rock trails are both super popular and almost always busy no matter what day/time of week. To get from there to El Monte Rd, you would need to be walking along some very busy roads for miles. Possible yes, but why would he do this? MOO