Further on your questions : The original survey for the Oregon & California's line from Dunsmuir, CA., to Ashland, OR., was to have diverted from the present line just North of Siskiyou Summit @ Tunnel # 13. It would have proceeded East then NorthEast to Buck Rock Mountain. After looping around Buck Rock, the line would have dropped downgrade to the South then West, rejoining the present line @ Dollarhide Curve just South of Steinman station. Another deviation was to have been just North of the stateline @ Cole, wandering around to the East before rejoining the present line at the South end of Summit Tunnel # 13. ( This surveyed Southern line appears to be the same route followed by today's Oregon Highway 273 from just North of the state line ( Exit # 1 on I - 5 ) to Siskiyou Summit ( Exit # 6 ). ) The above info is also from Signor's book Rails in the Shadow of Mount Shasta.
BTW, Oregon Highway 273 from Exit 6 North to Hwy. 66, as well as Hwy. 66 from there North to Ashland, is in reality old, OLD Highway 99. This stretch of road features a highway version of Tehachapi Loop for vehicles !!! As well, the wife & I have driven from Exit # 6 -- Siskiyou Summit & Ski Area, to Exit # 796 on Interstate 5 in California, using back roads that basically follow the tracks through the old stations of White Point, Colestine, Cole, & Hilt.