Is it reasonable to assume that Ranger Grayson's vehicle had a dashcam and that it showed a white car in the parking lot? I can't imagine a law enforcement car not having a dashcam, or investigators not reviewing the footage, and if the footage showed no car I would think they would not have done all that searching around Smith Water and there would have been media reports that they were looking for Ewasko outside the park.
If someone obtains the dashcam footage through FOIA, perhaps we can stop talking about the U-Haul theory and Sherlock Holmes? I would gladly abandon my silly theories if it shows even a blurry white blob made of a few pixels, unless of course that white blob is really a ghost.