The road to Gray‘s Peak trailhead was definitely impassible on 5/30/2011 by 4x4. The road had just enough snow and ice that, without chains, its just not do-able. However its a nice hike up the road to get to the trailhead. You can drive up a few hundred feet but then it was all snow/ice. To avoid having to reverse back down, save the 10 minutes, and just park in the parking lot.
***Make sure to hike on the dirt road as much as possible to avoid breaking through the melting snow and soaking your boots in the hidden puddles/streams under the snow and having to turn around...not that I did that...but I might have***