I agree that a tip is needed if they are in a remote location. I hope someone knows something about the neighbors habits if suspicions of him are justified. Does he own a backhoe and a pickup truck? Check any earth on them for clues to where they might have been used. Was there rain around the date the McFalls disappeared that would make burial easier?
I hate to keep comparing the McStay case to this one, but the McStays were buried in the desert not at all far off I-15 near Victorville. And here we are very close to I-15 near Littlefield, also in the desert. I think we can learn from their case. Although someone riding a motorcycle off-road discovered the McStay skeletal remains several years later, the disturbed earth of their graves and tire tracks were visible from earlier satellite photos on Google Earth once we knew where to look. So, rather than wait for Google Earth photos, I think drones could be helpful right now, looking along I-15, especially where the desert lies lower than the highway and is not visible to passing motorists. Someone working at night would not arouse the curiosity of passing motorists who might see lights. Unusual tracks and disturbed ground will stand out. These dont disappear quickly in the desert.