Consider Cabot stain Pewter Gray or Beechwood Gray. I cannot see the door you speak of.

Will the windows have dark or white trim?

Like you I'm not that crazy about the foundation. Matching the stone might be a problem based on the age of the house. Have you thought of a brick veneer over the foundation wall? Since you're not replacing the upper window I think you probably need to match the trim on the new windows with the existing ones. Can't really see the front door but maybe painting it a brighter color would help (making it a focal point). If you're interested in how the changes might look on your house take a look at my web site Creative Visual Concepts. Here are a couple of pictures of a project I did for a client.

A medium stain like the first photo from Creative is definitely a good choice. Much better. That is a beautiful wooded lot. What about a colored door and round stepping stones that curve from drive way?

Lancaster woodland home and garden · More Info

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I would see about matching the style of the stone you already have to do the foundation. If style can be found but color can't be matched you can always stain all of the stone. Your entry seems closed off with that "L" of stone on the right side. Maybe you should consider changing the "L" to an "I" and removing the little "bench" part of it to open up the entry. Unless you're changing the roof as well, keep its color in mind as you shop for stain. Here's a favorite of mine stained dark brown. The green trim is Ben Moore's Crisp Romaine. The combo works well in a wooded setting like yours.

Rustic Exterior · More Info

Rustic Exterior · More Info

Crisp Romaine 686 Paint · More Info