I followed this route last week. I think the description "Continuing up the mountain the trail crosses the same 4-wheel drive road and after a short distance, again meets up with the road but this time the trail makes a sharp right and follows the road until it reaches a locked gate"
should say "sharp left" which is consistent with the 2.2 mile description and what I did last week. I left your route description at my hotel by mistake, and almost missed this left turn. As I proceeded up a bit, I was unable to see the next cairn, and eventually spotted a cairn marking the left turn that gets you to the road.
The weather was relatively nice until I got to the crater rim, and ok until the summit. Then there was light to medium rain for much of my descent, with temps in the 40's. I was able to see at least one cairn during my descent, and normally two. I took some picture and will post a few this weekend.