All There in the Manual: a now out of print tie-in novel The Dukes of Hazzard Gone Racing, is set between seasons 4 and 5, detailing just how Bo and Luke came to join the NASCAR circuit (and leave Hazzard County). Though no explanation is given for Coy and Vance, other than 'your cousins just got out of the merchant marines and wanted to hang at the farm awhile'; they're given maybe three paragraphs and a one-line dialogue mention from Uncle Jesse.
Always Someone Better: What the producers and writers were hoping to do as they developed Coy and Vance, the idea that John Schneider and Tom Wopat were never coming back foremost in their minds. In one early scene, when Boss learns of Coy and Vance returning to Hazzard, he remarks that they make Bo and Luke seem like choir boys.
The Bus Came Back: Enos, who returned from Los Angeles to rejoin the Hazzard County Sheriff's Department.
Character Shilling: Dialogue throughout the episode to reinforce in fans’ minds that Coy and Vance were better and more daring than their predecessors.
Put on a Bus: Bo and Luke, to join the NASCAR racing circuit. This was necessitated by the departure of John Schneider and Tom Wopat.
Averted with Catherine Bach, who – according to some reports – also wanted to join Schneider and Wopat in their walkout. The co-stars advised her to stay, as her departure too would likely have meant an abrupt cancellation of the series ... or worse yet, a "replacement" Daisy that would have been rejected by viewers, worse ratings and a quick demise before the originals had a chance to return.
Shirtless Scene: Actually, in the opening credits with footage of Byron Cherry and Christopher Mayer working on the farm, to draw in new 18- to 25-year-old female viewers. (In 1982, John Schneider was 22, but Tom Wopat was by now in his early 30s, but likely already had their following, and "shirtless Bo and Luke" scenes had become decidedly less common after the second season.)
Replacement Scrappy: Coy and Vance. And the producers hoped no one would notice ... or better yet, that Coy and Vance would gain an even bigger following.