Horseman,
Thank you, especially for the info regarding the interiors. I wasn't aware that there was a difference between the interiors of a light weight and a heavy weight car either. The half a dozen Pullman cars I have traveled in (tourist rail) have all been wood finished (interior) with varying types (and therefore colors) of timber.
I was in Hobby Lobby a couple of days ago and did pick up both Model Master Wood and Leather paint for the purpose of doing the interior; however, the leather color has a deep brown look while the wood looks like a light to medium tan and not something that might be seen in a car. It certainly doesn't have that "first class" look about it. You can't really see it all that clearly but the interior is painted the same color as the window paint - Aged White. Your point about the interior light is a good one so I think (at the moment) I will leave the interior as is. The only other option I have (I think) is to fit lighting into the cars and that IS something that I would like to do at some point. Then I don't think the color will matter as much.
I have never used people on a layout before, not sure why, so I am really moving to an unknown area of the hobby. After looking at various makes of "People Sitting" from Noch, Preissler and Model Power - all of the people seem to have longer bottom half legs than will fit on the seats of the Pullman. As you mentioned, when I get which ever ones I do get, I am going to have to cut their legs off or at least shorten them to fit.
This/these cars are my first "serious attempt" at detailing rolling stock so I want to get them as good and as visually realistic as I can possibly get them. In effect, I want this steam train to be the highlight of my trains.