What you're describing is a picture rail, a nice feature. Lets you hang artwork easily and move it around without banging holes in your plaster. Being able to have one is one of the big benefits of high ceilings.

I wouldn't worry too much about having bedrooms different from the front rooms of the house. That would have been typical in an original Victorian era or A&C house. As Emerson told us, a foolish consistency is the hobgoblin of little minds.

I have never had an issue with bedrooms being quite different than the rest of the house so wouldn’t bother me . Is this the master that got altered?

Thanks—I remembered the term after I posted. It’s not the master, but I’m less worried about the difference than the lower ceiling and lack of crown molding making the room less finished. Do you think the picture rail will lower the ceiling? I also got a suggestion of beams (which we like) or a coffered ceiling (which we generally don’t), but have the same concern about looking lower. But I’m starting to think that’s not a real problem—many rooms with beams are 8’ or below. Thoughts?

Four/five inch door header and casings are plenty craftsman. A five and a quarter crown molding is as well.It's a bedroom. Don't obsess.

I would not do beams in an 8’ ceiling but Jans idea is a good one.

Keep the door trim consistent, and just put in a smaller crown or non at all. Stretching the door trim will emphasis the low ceiling

What is the style of the home? Crown molding is fairly formal and fits colonial style homes, depending on the style of the molding.

Here's an example of very shallow beams on an 8' ceiling in a casual farm-style house in a beach community. They are painted the same color as the ceiling so they don't stand out, but add a bit of interest. Crown molding in a house such as this wouldn't be appropriate, but only you know the style you're going for.

Hamptons Beach House · More Info

It's a bedroom? You might consider adding a shelf near the top of the wall above the door frame and all around the room as a decorative feature and use the shelf to display pictures and/or store books and/or board games and/or to hold some matching baskets to store other items. The few different finishing touch could well conceal the wall height difference.

I wouldn't be obsessing too much over this. Bedrooms have their own personality, and it doesn't have to be the same as the rest of the house. Good art, colorful bedding, a nice rug, will provide all the finishing you need.

You could use a crown with a similar but smaller profile.

Thanks everyone for your comments (sorry for the delay in responding--it's been a crazy time). Diana, thanks for the Beach house photo--I think that's a direction we're thinking about, with a smaller header crown over the door. Sorry for the obsession; partly it was an emotional response to finding out the builder changed the ceiling height without telling us.