I apologize if this comes off as pure speculation, but I think that imagining different scenarios could be important in cracking this case. And so to weigh in on the case in theory:
To me, it looks like a person or persons, injured or otherwise, were taken out of the side door of AL and K's house, and then placed up against the garage door to be loaded into the back of a truck (I am going from the drag marks that were on the side of the house, and the "purple" smear marks on the garage door--although one looks decidedly rounded, which could possibly signify a face or head injury). Let's assume for the moment that the current POI is responsible for the moving AL, K, and N from the house. It looks as though the POI had two options in moving these persons: either he backs up his own truck (the Green one) into the driveway, or he uses the Silver Tundra parked in AL and K's driveway. I suspect that POI in fact used the Tundra.
The scenario:
POI is caught on video going through the neighborhood at various points in the night in Green truck. He parks the truck, enters the house, and some form of "violence" takes place in the house. Not wanting to contaminate his own vehicle with any evidence, POI forces AL, K, and N into the Tundra, and transports them elsewhere. Only maybe he doesn't take a left down past the "1a street south west" (where we believe the infamous photo from the neighbors camera to be). What if he leaves almost straight down Parkhill Street, turning on Mission Road or to the McCleod Trail--from there POI could get to God knows where to do God knows what. In no way does POI necessarily have to leave AL and K's house in the direction that he would have been caught on video from what I see. He then returns the Tundra to the driveway, gets in his own truck, and drives to Ardie (obviously he would need a means of removing any evidence from himself before getting into his own truck--he could have even cleaned himself up at AL/K's home after the fact). The question is, where does the mud from the Tundra come from?
Essentially, I think that it is plausible that Tundra was used in transporting AL, K, and N, but that LE are currently looking for evidence linking POI to the crime scene (perhaps a weapon, blood, a hair in the truck). Means, motive, and opportunity, unfortunately, are not enough to place him at the scene definitively. LE may be scouring every inch of his clothes, vehicle, and property in the hopes that they find something to make that link.
My scenario aside, CTV has a great interactive map/timeline that you can look at if you're interested in having a detailed look at things:
http://www.ctvnews.ca/canada/map-and-timeline-calgary-amber-alert-case-1.1904896
I too hope for the safe return of AL, K, and N; and only post this with the small hope that it may help.