In this story, Mary's old glasses cause a fire, which is how Charles and Jonathan find the wrecked stagecoach. In reality, her glasses could not start a fire. They were used to correct Mary's nearsightedness, and the shape of the lenses is not the kind that will start a fire under the circumstances shown in this story.
The weight of that log would have far surpassed Nellie and Harriet's ability to lift it.
No mention is made about the 32 week preemie baby delivery needing specialized care.
At 43:31 they show Mary's glasses laying in the grass. Earlier in the episode they showed Mary's glasses and they were round with thin lenses and now they are more oval with very thick lenses.
At 5:21, Caroline sets the brake on the wagon to pick up the telegram for Adam. When she goes to leave she doesn't take the brake off. She just starts moving again.
At 37:55 modern day airplane contrails can be seen in the sky.
When Caroline is driving by the post office and Mrs. Foster stops her, she stops the wagon and sets the brake. After their conversation, Caroline fails to release the brake when she drives away.
When the stagecoach accident traps Adam and another passenger named Marge, Mary tells them about finding help and says, "I'll leave the canteen (of water) here for you and Marge." Adam could not get to the canteen, because the accident pins his legs under the coach.
Mary's long fake fingernails are back.
Mary says she is heading north and the sun is to their west.
However, she keeps the sun to her right, which means she goes south.
The stagecoach falls down a cliff and at 29:22, it rights itself for a moment. The inside of the coach is visible and it is clearly empty.