I would suggest doing a forum search. Several of us have modified our interior cabinets and there are many threads regarding staining/finishing the trim. As an example, our Cougar has what Keystone calls the 'cherry' cabinets. When we modified several of our cabinets, we found that red oak shelf frames and trim pieces stained with MinWax 'Gunstock' resulted in an acceptable match (for us).
Take your time, sand every thing you do to at least 150/200 grit, then stain and use two coats of poly. Good luck.