After Randy steps in the tar, he takes a couple steps on top of the trailer and leaves no prints, yet he leaves prints down the side of the trailer.
When Randy enters the Knights Of Camden hall the small airplane vehicle is to the left of the front steps, yet once he exits the hall the plane is now near the bottom of the front steps.
When Earl and Randy wake up in the school bus, the scenery through the rear window changes from a parking lot with a pickup truck, to parked along a roadway, back to the same parking lot, then to another parking lot with a large tree.
It is not possible for two drunks with no tools to quickly put a saw chain onto that motorbike, for a slew of mechanical reasons. But even if they did manage it, and in such a way that it would actually transmit some power to the wheel, the saw chain would snap instantly because the bike has so much more power than the saw it is meant for, and because of the bike's weight.
At 4:42 Jason Lee looked into the camera for a split second.
It is not possible to quickly kick down the gigantic, sturdy ramp from the top of the trailer roof. But even if it were possible, it would then lie in front of the trailer for the arriving policemen to notice. It is bigger than their car.
It is not possible for two drunks to quickly built a massive ramp so sturdy that it does not even shake when driving a 600-pound motorcycle over it. Especially not in the middle of the night in a trailer park and with nobody noticing.