Name That Trauma :: Reader Stickmann on a Diabolical Desert

There was what I believe to be a made-for-TV movie in the mid-late 1970s, and I suspect it was some type of supernatural anthology thriller. Promotions for it involved an RV in the desert, a woman in a wheelchair patting a dog or something only to fall down an exterior staircase, and a kid popping up from a circle of plastic milk crates or the like.

The striking portion of the film I saw on T.V. involved the RV: a middle-aged couple on vacation in the desert were attacked by large boulders rolling across the flat desert landscape. The genuinely terrifying part for me was that the husband first was trying to find out what these heat-blurred dots on the horizon were by repeatedly walking further and further away from the safety of the camper to get a closer look with his binoculars.

I think even back then, I suspected the massive boulders were "fakey," but that was just inconsequential to the terror I felt at knowing something is completely and hostilely amiss and yet still being compelled to find out what it is at the expense of your protection. The fact that the distance between the man and his means of escape in their presumably safe RV was shown in a long shot just psychologically added to the danger.
Eventually this RV would also be telekinetically commandeered while the husband was on the roof and the wife was helpless to override the steering wheel of the speeding vehicle, if that's any help in identifying this.

Does anyone know the title of this film?

Thanks again for your help! Take care.

Sincerely,

Stickmann

UPDATE: NAME THAT TRAUMA SOLVED! Special thanks to NurseKrud for solving it with GHOSTS THAT STILL WALK!