Adam wants a job in NY with his father's old law firm, yet it was not solvent enough to pay for the blind school rebuild after the fire. The firm may not exist after his death anyway.
At 15:50 min mark the blacksmith sign is still in place that bears the name of the town rapist from last season.
Mrs Oleson's red dress at the orphanage is made with the same floral calico fabric as the one Laura wore at her first teaching job.
Mary is seen with dark brown curly hair but the first hair perm came to America in 1905.
When Mary and Adam are leaving. Caroline kisses Mary on the cheeks and then says, "get along now, you got 2001 miles to go." It is less than 1500 miles from Walnut Grove to New York City.
In "The Reincarnation of Nellie", Adam & Mary move to New York. Laura hugs her and says she'll write, then says, "And I'll use my Braille writer so Adam can't read my letters". Adam had been blind for many years and only recently regained his sight, therefore is able to read Braille.