After 8 seasons Barnaby Jones deserved a better ending. The final episode is "The Killin Cousin" and its about Betty being stalked by goofy private detectives thinking she is killing her cousins for inheritance money. Barnaby rarely even in the episode. Its a bit silly and the detectives are borderline comedy instead of drama. The episode was used as a possible backdoor pilot where Betty goes to work for these goofy detectives.
I think there should have been another episode for Barnaby and the cast to say goodbye.