Jim - there's a sign pointing north along the summit on Monitor Pass pointing to Leviathan Mine. Can't be missed. However, not sure about your one connecting down the east side of the Sierras to Hwy 395.
Also always wanted to run up to the Fire Watch Tower at the top of the mountain that you can see as you ride up the road. I think there someone may have posted pics of it previously.
Only thing I recall with regards to the Leviathan Mine is John (Far_Fast) may have mentioned it before. What I find interesting is you can clearly see it on the satellite 3-D maps, but the resolution of that part of the Sierra Nevada is poor.