The subject of moving rocks in Death Valley was brought up recently and happened to inspire an idea. One video found on YouTube and often associated with webpages discussing the phenomena distinctly shows the rare occurrence of water crawling across the valley floor suggesting water may indeed be a catalyst coupled with wind currents. The problem is that nobody has ever seen the rocks physically move though Paula Messina tracked several rocks using GPS to determine their tracks.
Geologists have pinpointed a location suggested to be the starting point for most of the rocks and the GPS map observation from Paula shows several rocks moving away from one area. Couple this with Death Valley being the location of the lowest point in the United States, MysteryPile's theory states that there is a slight decline in elevation, enough for the rocks to slide, leaving trails behind from their last point. We believe the answer might be as simple as an accurate land survey grabbing a line of sight from the rock face believed to be of origin, and the ending points for current rocks in position. The angle of elevation may be moderate enough that it tricks the human eye while catering to the mass in rock. The creeping water definitely suggests a slope of some type which may soften the surface allowing the rocks to move easier. Another twist to this theory involves the entire Death Valley "race-track" area moving in a very slow and casual double sea-saw type motion where the rock origin end lifts enough, causing rocks to break free and fall to the valley floor while shifting existing rocks.
Together, these ideas may answer why rocks closer to each other may take on different paths as their masses differ slightly enough to change their trajectory during tilting or expending their potential energies over a steady decline in slope. Combine the land survey results from the origin and then from rock to rock with the overhead GPS positioning and a three dimensional picture evolves, possibly one describing more about the geological processes happening under Death Valley.