Nyack CA in Dec. 1982, cigar shape, lasting about twelve minutes

I was in California, on Highway 80 heading southwest just passing the glider airport (I think that’s Nyack-Blue Canyon but if not it’s the one to the east [left] with a wind farm to the west [right]).  It was the early Eighty’s, possibly November or December of 1982 or 1983.  
I observed what I at first took to be a blimp crossing the interstate from west to east.  I noticed it because from my scientific, weather, history, Navy, research and other experience I knew that it was very dangerous for a blimp to be that close to the earth so near a ridgeline so commonly windy, and I wondered if it was in trouble.  As I got closer I realized that it did not have a gondola, then that it was closer to a cigar-shape than the usual teardrop-shape, then that it had what appeared to be windows along the side midline, continuous and extending around the nose and tail as far as I could see (which I verified as I passed).  I saw movement behind the windows (which seemed translucent rather than clear, like looking through sand-blasted glass) that was purposeful, not random, rhythmical or cyclic.  I pulled over and stopped.  There was no sound coming from the vehicle, particularly not the propeller and/or engine sound I associate with blimps.  It continued east at about twenty mph. following the land contours until it rose and disappeared over the hills.
The color of the light from the windows was a sandy yellow and was the only light coming from the object.  There were no navigational lights of any kind.  The color of the surface gave the immediate impression of a silvery gray but upon closer examination it was actually metallic silver with some sort of mottled or textured surface.  Given that at that time my eyes were 20/5 and able to see in dim light even better that in bright light, the elements of that texturing had to be less than ½ inch.  I pulled out my compass and did a little trigonometry.  I figured out that it was between 70 and 85 feet long, and between 25 and 35 feet in diameter and that it was maintaining an altitude of approximately 200 to 250 feet.
Witness indicates that the date of the event is approximate.  PD