Two recent runs up Romero have gottne me a pretty good foothold on the area. Also took some friends on a hike up there recently; the picnic spot (described below) is gorgeous right now, with cold water in the pools and little hidden grottoes everywhere.
Starting at Romero trailhead, the steep gravel road goes up and across a concrete bridge. Just past the, it forks, with the left fork continuing up to the edison catway (see below). The right fork is the old Romero road, which used to be a vehicle path to Camino Cielo. It's still pretty wide most of the way up, but is blocked to vehicle traffic by a few boulder slides up near the top. Easily passable on foot, though.
Just a bit up the road from the fork, past a dry stream crossing, the Romero trail branches off to the left at an easily visible trail sign. The trail is 1.5 miles of moderately steep switchbacks and creek fordings.It's mostly shaded and a really nice run. About 1/2 to 2/3 way up, there's a lovely set of pools and little falls that I've dubbed the picnic spot. Beyond that, it continues up to a T-junction, which is the intersection with the old road. The right turn is the road headed back down (3.5 miles to the trail junction at the bottom). The sign pointing straight ahead shows it to be the trial continuation to Camino Cielo, and the left turn looks like the old road heading up to the same (leaving those for another day; it's a good hike just to get to this point!). The loop is about 6 miles total, up the trail to this point and back down the road, and offers a steep up and relatively mild, gradual down, which is good for the knees. The return road has a single notable fork at the point where it snakes around the East side of the lower peak, where a left turn will take you down into Toro canyon (according to
Ray Ford's site).
The left fork at the bottom is the Romero edison catway, the road used by Edison trucks to service the powerlines I assume (never actually seen any trucks on any of those roads). It is VERY steep and often dusty/gravelly; you'll get dirty and slip a few times hiking up these roads.
The catway heads up about a half mile, and then there's a turn-off headed back to the right. This turn steeply climbs to three iron trees that stabilize the powerlines on the West side of Romero canyon (from there, they drop across the canyon and are next stabilized on the other side, off the Romero road). The road ends here, although there is a trailhead pointing up the canyon wall; it was roped off on the date I was there (8/24) with a sign that stated "CLOSED due to rock slides, 8/20/07 until further notice." I'd like to explore this at some point; my guess is that it connects to the upper road fork described above.
The main catway dips down into a little hollow, than climbs steeply to a saddle, where three more iron trees hold the lines going over the ridge. Here, there's a little trail going up the sub-peak, but it goes nowhere. The next sub-peak (further up the road) has a nice dark trail through tall bushes (feels like something out of Lord of the Rings) that ends at an overlook with a broken-down bench and a memorial stone for someone named Brad, who died in 1997. Too bad Brad's memorial isn't better cared for.
The catway finally ends at some final iron trees that are the last before the power lines drop into San Ysidro canyon. Here, the Buena Vista trail begins. It winds down the canyon through a series of switchbacks and eventually ends at the Buena Vista trailhead which is at 832 Park Lane. From there, I ran back along Park Lane, Bella Vista Drive, and Romero Canyon Road to the truck. Apparently there's a connector between Buena Vista and San Ysidro, but I didn't see any such trail.
Here's a link to the google map of the trailhead; in hybrid mode, you can see most of what I've described (follow the road up to the first hard right bend, which is the low road fork just past the concrete bridge):
View Larger Map To Do next: upper Romero (upper trail junction -> E Camino Cielo -> Romero road -> catway connector trail), Buena Vista/San Ysidro connections.