In Season 2 "Haunted", Fonzie tells Richie, " My mother tried to lie to me when she was taking me to get my tonsils out when I was a kid"-but in season 5E06 he has his tonsils removed, "The Fonsillectomy".
From the outside, when Richie and Joanie enter the old Simpson house, there is a wall right in front of the door. On the inside, there is a staircase in front of the door.