The Vital Link is a fun, short-but-steep trail in the Verdugo Mountains. It's 3.8 miles & 1700' of gain round trip so it's fairly steep. I've hiked it a few times and I have to believe that I have better photos of it somewhere, but these will have to do for now.
You can actually reduce the distance and gain by driving further up Wildwood Canyon Park; I start at the bottom of the park. As with some other hikes in L.A. especially the Verdugos, the "summit" is a transmission tower. There's a nice slat chair too, so at least there's that. You can add on a little more distance and maybe a few hundred feet of gain by going to Verdugo Peak which, as you might have guessed, is home to another transmission tower.
One problem is that the trail gets enough traffic that there's some graffiti, and people needlessly create shortcuts (which increase erosion and just make things worse all around). I've also seen kids smoking up there.
TODO: find a way to carry my bike on my back so I can hike the trail up and take the fire road back down.