When the family first arrive at the beach, the pier is near the house. It is just as close to the bus stop when Lisa goes home at the end of the story.
Makes no sense that the Walton kids would spend a week at the beach in bib overalls and jeans when they all had proper bathing suits in the Druscilla's Pond rowboat repair story from Season 3 previously.
A British person would say "wardrobe" not "closet"
The Coast Guard ship that is visible about 35 minutes into the show, is equipped with modern radar systems (modern for the Seventies that is) which did not exist in the 1930s and 1940s, the years in which the show is situated.