Out of Doors Mart may have the tambour door material (it is expensive btw) and maybe the plastic parts you need. However, I am not clear just what plastic you are referring to.
The original trim is available in white only. Inland RV had it and probably Out of Doors Mart too. About a buck a foot, kinda pricey. You can make your own from either Formica or cut down vertical venetian blind slats and it will look great. Blind slats from your local blind dealer.
BTW, the old banana yellow color of the trim was not original, but a result of sunshine and UV damage. The trim was a slightly off white to begin with and looks much much better that way. If you have old banana yellow end caps or AC parts, or the refrigerator vent, they paint very well with Krylon Fusion Paint for Plastics, Satin white. You can get it or order it at places like ACE hardware. Satin, not gloss is best.
I don't know if you have any chocolate brown cabinet handles, but if you do, and hey have turned to a kind of frosted old chocolate color, they can be repainted with Krylon Fusion paint for plastics, gloss brown, available most easily at Wal Mart.