Thank you for these.
My hunch is that you are correct. The markings indicate that the police were interested on both sets of tracks as well.
My further hunch is that the deeper tracks are from a heavier vehicle, such as K's camper truck. It does appear that two vehicles departed the scene. Of course, it might just be tracks that had been there a while, but still, the police seem to be interested enough to mark them.
The location of the body IMHO indicates that it would have been noticed before too long. This fits with reports that a driver reported it to police responding to the burning truck.
So, if true, this gives a scenario of the two suspects leaving the scene in the two vehicles, heading a mile and a half down (south) the highway, then burning the truck. This begs the question; why so close to the body?
A theory of mine kind of fits into this. I've long wondered if, after the murder of the couple in the van, the suspects headed for the Stuart-Cassimir highway (37, that runs through Deese Lake) as a route out of the area other than the Alaska Highway (it's the only one) via Watson Lake. However, the truck, being fairly old and driven by someone I suspect knew little about engines, began acting up (maybe they didn't put oil in it - trucks that age do tend to leak). So, they were stuck in the Deese Lake area with a poorly running truck, with a manhunt getting underway over on the Alaska highway. So, they decided to murder someone and steal a car, and the professor had the grave misfortune of being in the wrong place at the wrong time. As for the burn site of the camper truck, maybe it just couldn't go much further. (on the other hand, given what they did with the RAV4, they did not seem to care, so it might have just been a convenient place to pull in and burn.).