When Larry reads out the title of a student's "coffee table book" he says "One
Hundred Girls I'd Like To Pork" but his lips are clearly mouthing the final word as "Fuck." This line was presumably overdubbed to avoid an R rating.
When Owen sits on the porch (with the door open), his mother sits in her chair in the living room, and Larry lies down on the rug between them. Momma sees Larry on TV and yells "There's a murderer in the house!" at which point the camera turns back to Owen, with Larry notably absent from his place on the rug. The camera then returns to Momma calling the police at which point another cut is made to Larry awakening, lying on the carpet again in his original spot.
When Owen serves Larry breakfast, he takes the jelly jar in his left hand and starts to grab the spreading knife with his right. Mrs. Lift yells from the other room, and in the next shot, Owen reacts, now holding the already-jellied toast in his left hand.
The locomotive shown on the train is a switch engine. Switch engines are not used on road trains or Amtrak. Switch engines may be placed in the locomotive consist on road trains, however they are typically either isolated or dead-in-tow.