Ever notice that on an interior wagon scene these wagons look like they could hold a king sized bedroom suite? Then when an outside shot is used the wagon might be maybe 6 by 4 in size. There's always room for a person to sleep long ways in the wagon with several feet between the person's head and the front of the wagon and his feet and the rear of the wagon.
This might be a slight exageration but there is a noticeable difference between outside and inside shots of the same wagons.
I was just noticing the same thing watching "The Last Circle Up" (S7 E32), although I imagine most episodes showed similar scenes. The exterior width of the farm wagons (they weren't Conestogas, either on the show or in real life) was four feet or less, yet an interior shot showed a man lying in a bed with furniture on both sides of him and in front of him.
There have been a few shows where I have wondered for years or decades how to fit the interior sets of a building into the exterior sets, since it looks like the interiors are larger than the exteriors.
And in science fiction shows like Lost in Space (1965-68) and Star Trek (1966-69) space vehicles like the Jupiter 2 or the shuttlecraft Galileo 7 seem larger on the inside (probably for ease in filming in them) than on the outside (probably for lesser expense in building them).
Thus not caring enough about making the insides and the outsides fit seems to be a very common factor in Hollywood production design.
That reminds me of the scene in "Star Trek, the Motion Picture" when Kirk and other crew members go out a hatch and walk around on top of the disk of the Enterprise. It looks far too small.