We started at the west end of the trail. It had snowed two nights before, so the snow was still resting on the tree branches, and the snowplows were still working on the paved roads. Because we were in a 4WD, we didn't need to put chains on at the CHP stop, and drove up to the trailhead with our normal tires. As we left the plowed road, we switched to 4HI, and had no problems. My wife Maria especially enjoyed being out in a snowy forest, some thing she misses from growing up in Massachusetts.
At the trailhead, even in 4LO, we started sliding, and decided to put on the chains. After airing down, we met another couple, Justin and Sabrina, who were also planning to drive the Holcomb Valley trail, and decided to travel together. They were very nice, showing us some places they'd seen before and generally being great people. They also told us of their favorite burger place, Get the Burger (http://www.gettheburger.com/). Their description made it sound like something we'll have to try, although we wanted to check out trails in the other direction this day.
Holcomb Valley trail is pretty easy. There were a few places where a high-clearance vehicle came in handy, but no real obstacles. There was one curve where it was icy enough we both slid to the inside corner and had to drive hugging that wall until it flattened out, but that was the worst of it. Without the ice it would not have been anything to notice. We saw a few deer, and tracks from rabbit, coyote, squirrel, and birds (including a takeoff wipe).
The east end of the trail is near the dump north of Big Bear. Perhaps it was the snow, but I wouldn't have known it was a dump except for the sign.
We had a great time. Nothing difficult, but just a great time being out and about.