Revealing mistake: Throughout most of the episode, The Car is a standard black with chrome trimming. But at the end it's suddenly beige when Johnboy and the kids are polishing it for their first ride.
Suggested correction: At the end it's not "suddenly beige." Mid-episode Mary Ellen mentions a family project to, "Design you a new-looking car" and Erin adds, "We can paint it." Soon John-Boy says, "I'd like to paint it a nice dignified shade of tan." In the penultimate scene John-Boy drives Hyder and Martha Rudge back home. Time passes offscreen. It cuts to the final scene with Mary Ellen and Erin placing their new cut/sewn seat covers in the newly painted tan car, and nobody is "polishing it for their first ride."