Near the end of the movie Velvet stops at a one room shack (outside view). Once inside, it becomes a ranch house with 20 foot ceilings and a piano. Obviously two different buildings for the scene.
The stage-coach bandits merely take valuables off the passengers' persons; the robbers are not shown removing the money-chest, yet it is seen in their possession after the coach pulls away again.
In the final scene when McCrea is talking to the girl a car is seen driving by in the background.