Using D&RGW caboose 04990 as an example, the interior is painted light green on the walls, while the interior ceiling is painted tan, the tan is also used on the top foot or so of the walls. The ceilings above the platforms are painted oxide red. The underframe shows evidence of also being painted oxide red at some point. A look at caboose 0574 at the Georgetown loop confirms this color scheme. (0574 has not been repainted since it left the D&RGW)
Passenger cars are one case where the trucks and underframe were painted black, while the carbody was pullman green. Using D&RGW coach 280 as an example, the entire underside, along with the platforms and steps, was black. Only the sides and metal portions of the trucks were painted black, the other wood parts were unpainted.
These examples of course only reflect what the D&RGW was doing towards the end of operations.