I can't see a chair rail in the wallpapered room... Different rails heights would make me crazy so I would try to remove one of them. If this isn't possible at this time, paint the rail the same color/sheen as the wall. There is no reason to highlight it.

I don't think the trim at the top of your paneling/wall paper? would be thought of as a "chair rail" so I think you should just proceed and not worry about it. The two rooms are different. The higher detail could be looked at more like a picture rail.

Well that made me laugh! : )

That's picture rail in the front room, not a chair rail. They look fine together but you can easily remove either or both.

Hi, Joanne--

Ida is right - you've got chair rail in your dining room and picture rail in your living space. These will take on a totally different appearance once all that wallpaper comes down, so I'd eval then, but expertly installed millwork is always worth a second look. Nice touches to have in your space if they work for your vision of it going forward.

Is removing your ceiling popcorn in your plan, too? If so you'll be making a big transformation on your painted surfaces all at once - exciting stuff!

If it were I I would take all the wall paper down. I'd leave the chair rail in the dinning room and add picture molding to the bottom and big once to the top too. like this. paint it all one color. subtle, but beautiful.