It's been decades since I've reread Burroughs...but from the trailers I've seen of the upcoming movie (which looks great, IMO) John "gets to Mars" in the film with the assistance of some bit of technology he acquires (finds in the cave in which he takes refuge?)... I don't recall this angle.

I thought John gots to Mars by simply "wishing on a star" so to speak...? (Some sort of Indian magic involved, as opposed to deus ex machina.)

I also recall that on Mars, there is an "extra primary color." A fascinating idea, but I don't suppose even Hollywood and all the CGI on the planet could pull this one off on the silver screen...