As someone who has watched Bonanza with my dad and seen basically , nearly all the episodes ... the formula was basically simple.
1.) Cartwright's get in trouble ...usually one or all of the son's , their Pa comes to save them.
2.) Ben gets in trouble , the Cartwright boys go to save him.
3.) Little Joe mostly falls in love in a lot of episodes. The girls either A) Die , B) Leave or C) Fall for someone else.
This repeated thousands of times. In fact the formula broke apart the later seasons by 1965 when Pernell Robert's left. In 1964 , they introduced a nephew Ben Cartwright never knew he had...called "Will Cartwright".
The idea was to have one of the women that Adam falls for , marry him and leave in the season finale for the East. Pernell Robert's wanted out that previous year and producers decided they wanted to keep the 3 sons and their father deal.
Guy Williams was in 5 episodes that season and was supposed to become a main cast member. Instead fan reaction to him wasn't received well and the producers convinced Roberts to finish out the season. The episode he was supposed to depart with the girl , Will Cartwright did instead.
After Roberts left life went back to normal somewhat for the Cartwrights. The formula was a bit broken as now it was 2 Cartwright sons (Hoss and Little Joe) now joined by a ranch hand named Candy (David Canary).
Of course this formula would shatter for good by 1972 , Brian. In that year Dan Blocker died and his character "Hoss" was written as to have passed away. In the opening episode (which should really be the series finale of Bonanza) Little Joe (who is now grey headed) marries and his wife is killed.
Called "Forever" it has Joe go on a mission to kill those who did it. Candy (who Landon pleaded with producers to rehire) goes with him. At the end you sense the heart break Joe and his father shared. The family was forever shattered. Adam was gone and rarely mentioned , Hoss was dead and Little Joe was a broken man. His days as a lover and leave em type...done.