Interesting car arrangement but I think it was somewhat typical for the era except the short length.
From what I can see - rear to the front - 5 pairs of walkover seats (20 skinny passengers) - Baker heater in center of car, toilet behind it with the angled door (dry hopper chute just ahead of the queen post?). The passenger compartment interior view shows a door to the baggage area to the far right, exterior view suggests the car end had window on both sides.
This car evidently had a small early mail apartment. Notice that through the open door you can see some kind of cubbyhole system with maybe bag racks below. This was before RPO apartment arrangements became standardized. The first window next to the baggage door is for the RPO apartment (or closet if you prefer), but would be in the side aisle on the opposite side of the car. The Baker Heater radiator lines wrap oround the compartment.
This appears to possibly be a very early triple combine even as short as it is. So did Uintah actually have an assigned RPO clerk during its operations? I would have thought it was closed pouch service, so is that what the closet was for?