Just have good boots and stick to the fire road or you could end up knee deep in snow.

A few friends and I went up to the area this past February (same day of that Mt. Wilson Outdoorsclub-related fatality). We were going to hike SG Peak, but the JPL trail to the summit was snowed in at the trailhead. We didn’t think it was wise to route find since we all knew we lacked neccessary skills and equipment. We ended up hiking up to Mt Disappointment. Despite certain icy sections of the road, we managged cautiously and made it to the summit. The view toward the valley and the high country was pretty good once on summit. This is despite the communications equipment.

When I went up to San Gabriel, it had only a dusting of snow from a very small storm system. All of the ascent from Red Box is on north-facing slopes, which will hold that ice and snow longer than the southern face if there’s a low snow-line like there was with this recent storm.

Coming up from Eaton Saddle is a sunnier route, but you are correct in that the trail near the actual peak’s summit does get steep, and should — as all trails — be hiked with caution during the winter.