I've been in enough movies to know that when you're on the set and you start shooting you're looking at playback and you get a sense of what it's going to be like.
I think you just assume that your memory is just sort of a video playback of your experience but it's nothing like that at all. It's a complete refabrication of an event and a lot of it is made up because you're filling in spaces.
Family trips to Yellowstone and to what are now national parks in Southern Utah driving the primitive roads and cars of that day were real adventures.