The headliner would be off-white beige from the top of the doors all the way around.
The instrument panel would be matte black.
As Ben suggested, black or dark brown for the door panels, dog house, seats and sleeper side/back padding.
The bunk can be any color you think a blanket and pillow could be.
Optional colors for KW at the time:
Black, red, green, brown. The Splendor interior had the seats in a red/tan red/tan red/tan striping. (several colors available, I used the red/tan for explanation).
Tim