I started on the road between the small white building and the big tree (cottonwood?) -- there's a junction there, so it seemed like the obvious place to start. 99% of the way (sans the summit itself) you're on a dirt road and sometimes it's a little rocky, sometimes it's rather soft. Some sections are surprisingly steep, but you get a few breaks of near-flatness or a short downhill. The final, very long switchback allows for greater speed. There was a cluster of clouds at the summit on the day I went up there, and the top of the mountain had received a light dusting of snow the night before. This combination meant the summit was a drastic twenty-degrees F colder than the trailhead (50's to 30's! maybe even lower). There was frost on everything and the wind definitely had a bite. The cloud also prevented me from seeing any of the summit views, sadly, but it was still a very beautiful and interesting experience. The land is very exposed and is basically high desert with junipers down lower. Star Peak doesn't look like much from I-80, but the whole ridgeline is very alluring, especially when you're up there! The descent is FAST, almost out-of-control fast, made all the more difficult by the looseness of the dirt. Fresh legs are recommended!