unless she was possessed, tripping on drugs, completely delusional or running in terror, she would have found the road imo. theoretically you are right, but she was not walking blindfolded with earplugs in. yes, they were in the middle of the desert, but they were still very near a road.
eg... if you live near a coast it is quite easy to orient yourself based on where the coast is. if you are in relative flatlands, within a few miles of a road, and agile enough to reach high ground/climb boulders (which 69 yo barb was), you can find your way back to the road.
i say this, because i also have been out in this and other deserts. and other wilderness areas. some places aren't easy to get lost, even for directionally impaired ppl. this was one of those areas, based on sroad's descriptions and photos, available in media thread, combined with roberts first-hand description of the area and recounting of events.... Barbara did not wander the wrong way by accident.
sixth or seventh time i've felt the need to say so, and i say so quite firmly.
sure, it is possible. but IMO this is not a believeable scenario. Even less believeable to me than random abduction.