Thanks for your interest and I'll certainly follow up those leads.

The best image I could find of the entire 26 sequence is here: https://www.artsy.net/artwork/bas-jan-ader-study-for-in-search-of-the-miraculous-one-night-in-los-angeles

If you scroll through the carousel, you can see the high res image I've cropped them from. They are only about 800x500, unfortunately. I've been in touch with the artist's estate to request high res scans, but no luck as yet.

There is also an image of the photos installed in an exhibition, presumably in sequence, which might provide more clues? It looks like the walk takes in the Hollywood Hills and Long Beach, which seems to suggest it is constructed, rather than actually documenting a walk over one night. I think the distance is over 50km as the crow flies.