A tough call, nziegler, judging from the pictures you have at least two different types of molding going on--the one which troubles me most is the one of the base in the 'alcove', where it doesn't join up properly--was the one piece removed and not put back right, or is the base not original? Such a corner just wouldn't have been done that way at the time.
How much ceiling height was lost by the addition of drywall: less than an inch, or was it installed further below the original ceiling height?
From what I can tell from your pictures, I would do without crown molding at all--the earlier portions of the house could have had stencilling there, but the 'Greek Revival' sections would probably have had plain painted walls. Unless the house was high style, the simpler look would have been the norm. Elaborate crown moldings are generally later Victorian touches from the easy availability of machine-made steam moldings. With lower ceilings like you seem to have, aesthetics would prefer clean lines over fussy details in that era.

columbusguy1, you did notice another issue that we are wrestling with. The baseboard molding is different in every room and actually in the family room there are two types of baseboard molding in the same room. We are thinking about what we want to do with that... leave it to keep it as original as possible, change out just the parts that are really bad (examples: the molding in the parlor where they are not even mitered to meet properly and the molding in the dining room where a patch is very apparent where they removed a door). The other option is to pick one profile that we like and carry it around in the four adjoining rooms. Thoughts on these options anyone?

Back to the crown molding issue. In places the drywall adds just about an inch and in places I believe that it adds several inches due to leveling the ceiling from a lot of rocking and rolling which most old houses have. I like the idea of leaving all of the rooms without crown, but DH wants it. I would like to find historical examples where there was never crown to show that it is accurate, or to find a good crown solution for dealing with the lack of height between door/window casings and the ceiling.

My Greek Revival House has no crown on the top floor, and apparently never did since some of the junctions are original wall against original ceiling.

On the third floor it has cornice but it is not crown at all, it is much more horizontal than vertical.

Here is the fourth floor, the window trim is not original to 1838 here,

While the main room is simpler: essentially one less "bead" on the horizontal and vertical than in the hall. But it extends further out than down.

Totally off topic to your discussion, but the main floors had very elaborate cornices, but the ceilings were quite tall (14'). This is circa 1839.

I did a very small version of the part of the moulding on the ceiling of this apartment over my kitchen cabinets by using baseboard with an ogee on the top edge place flat against the ceiling with the ogee facing out of course and a small peice of cove between it at the wall. It extended out several inches, but down only about 1-1/2".

Fads come and go in the remodeling world and at the moment crown molding is very much in. In your case - apologies to your DH - I'd skip it.

First, crown molding is not terribly authentic for a house of this era except for those that had extremely high ceilings and/or were far more expensive and elegant to start with. Second, unless the sheet rock ceiling was very carefully leveled before it was installed you're going to have a hard time installing any sort of molding without gaps, waviness, etc. which leads to a very odd look. Third, crowding the space between ceiling and window casing will also look awkward. All in all, a neat joint between ceiling and wall done with tape and joint compound will look better than molding.

That trim around the windows and doors was added in the 20's or 30's , it screams art deco. Something that crown moulding does is shrink the room along with all the maladies mainegrower mentioned.
My good friend lives in an untouched 1st period house N of Boston (1698), I can tell you it looks nothing like yours

I have to disagree, I live in a neighborhood of Greek Revival houses and there are variants of the trim pictured in the original post. The dog ears around the doors, the corner blocks, the plinths, everything.

The trim in the house pictured looks out of scale and exuberant because it was grafted on to a muc older period house that was different in scale.

The federal period houses a few blocks down are significantly smaller, and the pre-Revolutionary ones even further down are smaller still.

But since houses don't exist in a vacuum, people update them with the latest, so the house in question got Greek Revival details at Greek Revival scale grafted into a smaller house.

It's interesting that you mention Deco though, because Art Deco furniture looks beautiful in certain styles of of Greek Revival houses, because there are certain commonalities.

jonnyp has never seen greek revival trim in his life.
Casey

Thanks for the comments, everyone. Yes, the house definitely had multiple transformations done to it over time and the oldest part of the house no longer has anything that resembles Georgian which it probably started out with. I think that we are going to leave the walls without crown molding. :-)

But... I have another question for you folks that I just cross posted in the decorating forum. I am trying to find a source of the base cap molding that is in the dining room and parlor. See the link below to see dimensions, photos and drawing of the profile. Thanks!

Here is a link that might be useful: Link to Base Cap Question

This company reproduced my window casings. I needed more and what was there in some areas was very damaged and covered in lead paint. It was cheaper in the long run to reproduce it. They may also have a profile in their library that meets your needs already.

Here is a link that might be useful: BH Davis

Our home is 1700s we have it in alot of the rooms here even before we restored the house.We kept it all.like it.