When Peter is held up by the train at a crossing, the caboose is plainly marked SP (Southern Pacific). But he is supposed to be in New Jersey. Although there might be SP box cars in New Jersey, there would not be an SP caboose.
When Peter is making breakfast for Ellen, as the table is first set, there are six doughnuts on the plate in the lower left corner of the screen, but when they sit and begin eating and discussing what there is to eat, there are only two.
After Peter gets the car from the "thief", Peter's luggage is in the back seat. As he stops the car to pick up Ellie the luggage falls to the floor. When Ellie steps into the car the luggage is back on the seat. When the car pulls away, the luggage disappears again.
As Peter is singing and threatening to take off his pants, Ellie begins to bolt behind the hanging blanket. A half second later there is a shot of Ellie looking at him for a solid second, and then bolting to the other side of the blanket.
When Peter is chasing after the police escort that Ellen is riding in, the road has a solid line down the middle. As he pulls over to the side of the road and gets the flat tire, there is no line down the middle of the road. It is a different road.
When Ellen asks the autocamp owner to use the telephone, she is refused permission and directed to the sheriff's office. However, a newspaper reporter later says that she telephoned her father from an autocamp.
During early portion of Walls of Jericho scene, blanket hanging from rope is nowhere near rear wall, allowing views into both beds. Moments later, when Ellie considers jumping out window on her side, curtain is flush with wall.
When Peter is explaining to Ellen how he gets undressed they show him in a frontal shot and Ellen is leaning with her back against the wall watching. When he gets ready to take his pants off she gets scared and starts to leave coming forward off the wall. Next shot is a frontal of her and she's back against the wall and starts to leave again.
In the opening scene, Daddy's yacht is supposedly anchored off Miami. Yet in the distance are tall coastal hills, similar to what one might see in Southern California. Such a topographical feature is unknown in South Florida.
The goof item below may give away important plot points.
Toward the end, on the morning of the wedding, Ellie is in her bedroom in her wedding dress. Her father comes in and they talk about her love for Peter. She is weeping and eventually gets her father's handkerchief. At one point, she sits on a stool and he stands by her side. She is holding the handkerchief in her left hand. Her father puts his hand on her shoulder. In the wide shot, she reaches up to hold his hand, still holding the handkerchief. In the close shot, the handkerchief disappears. In the subsequent wide shot, it reappears.