Inside trim is all oak. Builder photos from archives confirm it was always oak. The end doors are 100% oak currently, and it is quartersawn with visible rays. I think it is important to stick with quartersawn oak for new doors, to assure stability -- resistance to warping.
Most of the current windows are mahogany, or at least a similar tropical wood. The single original window is also mahogany. This wood is used for stability in a very tough application, not to match the rest of the oak trim. At the time this coach was built, even foundry patterns used mahogany. The window frames are 11/16" thick, not very substantial.
I am sure mahogany or an equivalent is available at most hardwood suppliers. I have seen it in Austin.
Harold.