I work at a hospital & in the intensive care ward the patient beds have lifts above them for moving infirm patients.

Sort of like these rails in the video but they have two parallel tracks with a cross track. See pic. The hoist hangs from the
cross bar so it can move anywhere. Much lighter duty, of course. McMaster-Carr sells it.

https://www.mcmaster.com/trolley-roller-track-systems




A friend made a multi adjustable rack for his trailer, I'll post pics later. I plan to make one similar with wheels so I can remove
it from my trailer & wheel it around my workshop. One for your van which, when unloaded, can live in your van?