If you get tambour that is ok, but has yellowed, I have found it can be successfully (that is it looks great, like new) painted with Krylon Fusion Satin white paint for plastics. To make it look really good, the material must be removed from the tracts and done with several thin coats, but it is worth the effort. All other plastic in your Argosy (or Airstream) which has yellowed to what I call "old banana yellow" can be painted in the same way and the results are well worth it. That includes the inner end caps, the refrigerator vent, and the interior Air Conditioner cover. The end caps have to be painted in place most likely, mask and removal of all the pieces around them. On a nice warm dry day, using a large box fan and a simple mask for your own face, you can paint inside with spray cans successfully.
Don't try to paint the yellowed insert material in the trim, it can be replaced easily with either formica strips in a pattern you like (or neutral white) or cut down vertical venetian blind slats may be used. They are available in lots of colors and patterns.