Back when on my rolling stock binge, I kitbashed and scratch built a number of
cabooses, as I favor and use side door, combine, and drover's cabooses. Some
were available in brass, such as, I think, three from Bobbye Hall, including a
T&P sidedoor, someone did an ATSF sidedoor, the remains of a prototype sits? at the Rhyolite RR station in Death Valley, and Third Rail did a UP sidedoor in two colors, but in three rail, demanding no truck and coupler change. Having been in HO, I am annoyed by what isn't available in three rail, and try to fill those gaps. MTH did do a side door, but you wouldn't recognize my kitbash of it. And then I got whimsical and decided to build long and short cabooses of various flavors. This photo and another of one of the old ATSF ones with a seat, and no cupola, on the roof, should bore you enough, but is just a sample.