Continuity mistake: When the stagecoach enters Tonto street, it's shadow switches sides between angles.
Visible crew/equipment: In the scene where Ringo (John Wayne) finishes talking to the Marshall and walks toward the stagecoach, watch the right hand top side of the stagecoach, the camera with a film reel can be seen and as Ringo walks towards the stagecoach it gently moves back behind the stagecoach. The camera appears to have some kind of a covering of black cloth and also the hand and part of the arm of the operator can be seen.
Factual error: The distance from Lee's Ferry to Lordsburg is over 500 miles, not a trivial distance by stage coach. But in fact, the stagecoach travels several times through Monument Valley, back and forth. Monument Valley is on Navajo Reservation, nowhere near the Apaches or Geronimo.
Continuity mistake: In town, towards the start of the film, it goes from a street scene in front of the coach to a shot of Andy Devine sitting on the coach. From the street you can see the buildings behind the stagecoach, but when it goes to Andy sitting on the coach, the background is sky, not buildings.