I've been involved in missing persons searches before. Tactical trackers are pretty good at finding a path, even in bog/muskeg. Moreover, people tend to leave a ton of stuff along trails - candy wrappers, cigarettes, beer cans, wet clothing, bug spray, water bottles, shoe laces.
The police note that no cars have been reported stolen. Northern communities also have a ton of quads in them, which might not be under immediate supervision. A quad, with a jerry on the back, could travel ~200KM or more. These are easy to start without a key.
JMO.