If you want to do a better job on that caboose (from a modeler standpoint) start with a Trix/Model Power body and frame. The bolsters are correct, and the basic body is better than the Atlas. Replace roofwalks and rails/ladders with brass parts and it's not half bad, I'm re-doing another pair. They are dirt cheap on the auction sites, you'll likely pay under $5.
Of course, if you want a real post-1969 ATSF Ce-1 or Ce-2, Intermountain has them. But not for $5. And the current run is dead-on for ATSF paint and detail, although fragile with all that add-on detail.
And if you find a current Atlas body paint scheme you just have to have, the bodies do transplant onto other frames including the Trix and even a stretched Kato if you want electrical pickup. Yeah, its a project, but a good one. No ill against Atlas, it's a very dated product, but as a Trainman product, they're pretty much telling you that from the start!