From Eastern Oregon the key is to get to Fallon, NV which is near Reno, NV.
My brother likes to go from Biggs on US97 to La Pine, OR, 30 miles south of Bend, then onto OR31 going southeast to Valley Falls, OR to join US395 and on south to Reno, NV. Don't forget to take the Standish shortcut to avoid Susanville, CA. From Reno go straight east on I80 to Fernley, NV, then take US50 to Fallon, NV. The problem with this route is the Oregon High Desert can get cold.
Leslie and I live further east in Eastern Oregon. We take I84 southeast to a few miles past Ontario, OR and turn south onto US95 in Idaho. US95 goes south and back a little west to Jordan Valley, OR, to Burns Junction, OR, to McDermitt, NV, and to Winnemucca, NV where we get on I80 going East. Well before getting to Fernley, NV (east of Reno, NV), we take US95 going south to Fallon, NV. The problem with this route is the weather and steepness going up Cabbage Hill just east of Pendleton, OR. My coach with toad can go up Cabbage only 47.5 mph. Also a potential problem is the weather in extreme SouthEast Oregon due to the High Desert.
From Fallon, NV just go south on US95. We turned right 60 miles south of Tonopah, NV at Scotty's Junction, NV onto NV267. From Scotty's Junction it's only 27 miles to Scotty's Castle (which is on the Eastern edge of Death Valley).