Teri Cleeland (USFS) suggested that there could be a 1920s section of Route 66, extending westward from Fortynine Hill towards Parks. It shows well on aerial photographs: the USDA pictures Teri has, and those available from the USGS (TerraServer). I drove on part of the section, using the GPS tracking capabilities on my notebook computer. Shown below is a printout of the area, with the track taken by the truck depicted in a darker shade. Notice the close agreement between the track and FS649 west of the apex.
About 0.5 mile southwest of the northernmost apex of the 1930s Route 66 alignment on Fortynine Hill, one can see the beginning of this alignment (1). It is an elevated roadway, not quite two carwidths wide, but narrowing in some places. I counted 5 metal culverts along this section. These are corrugated metal pieces, rectangular in shape, with a semi-circular coutout area (I assume for the drain pipe) on the bottom center of the long end. Here is one, located near the Interstate access near Parks. (This is not on the suspect alignment. I include this picture since the lighting was better here.) There are other culverts like this one farther to the west nearer to Parks.
At (2), the road washes away completely. Here is a photograph of eastern approach, looking southeast. One can see another badly contorted metal culvert in the foreground. This area is named McDermitt Springs on Street Atlas version 6.
At (3), about ten meters west of the previous photograph, one can see the elevated roadway, and the fact that it is fully two carwidths wide (notice the position of my truck). There is a piece of a metal culvert just left of center. Not seen in the picture is a length of 15/16th inch diameter steel rod, one end buried in the ground, the other end, threaded, sticking up.
At (4), the alignment joins a more recent graded and graveled roadway. It separates again at (5). The more recent roadway ends at (6), the junction with the 1930s Route 66 alignment. At (7), the suspect alignment rejoins the 1930s alignment, as shown in the picture below. I walked this last section between (5) and (7), and found pieces of currugated culvert. This section is elevated and twocars wide. The road marker cautions drivers of the concrete culvert one can see at the bottom of the photograph. Its southern companion has a 1931 marker on it. Notice also the large rocks placed on the older alignment. I suspect that these were placed there to discourage drivers from following the older alignment.