Well, they say that you should be on the trail by 6am for El Cajon Mountain, but my wife and I are not the early hikers, so we started this trail around 10am. Luckily, it was just a moderately warm day, so we were okay (and we did bring lots of water). But this is a LOOOONNNG hike, and the 3500+ ft of elevation gain make it extremely slow going, especially at the end where the trail is at its steepest. It is worth it, though. From the summit you have excellent views all around.

Since we started so late, we didn't make it back to car until way after sunset. Definitely bring a head-lamp if you're getting a late start. Also, trekking poles are highly recommended for this hike, especially on the downhill part.