Actually, most of them receive very little use. The trails on the east side of the mountain are mostly used only by climbers heading up the mountain, and those routes only consist of about 10% of the summit attempts. Even the more accessible trails are too heavily used.
Now, this is a mountain I know! I first saw it — well, actually its refracted image — from the top of Mt. Diablo, in the Bay Area. The conditions have to be perfect, but I knew someone who was fascinated by the view from Diablo, and he knew when to go look. it wasn’t a clear viewing, of course, but there it was. I’ve only been in the area of the mountain itself a couple of times, but it is a beautiful sight.