Here's a couple of links to maps and directions to the Jetty. The road doesn't require four wheel driving, and a Wrangler would do fine getting there.
http://climb-utah.com/WM/Maps/spiraljetty.jpg http://www.spiraljetty.org/#visinfo http://www.flatrock.org.nz/topics/in...black_rock.htm
Hope these help!
J Truman