I agree with the recommendation to get an architect involved. The house is a very nice design and you don't want to ruin it.

One general comment - Since you appear to have lots of land space, I would consider adding both an entertaining area and a master bedroom and bath on the 1st floor. It would make this a great transition home when your kids are ready to move out and you want to avoid needing to navigate stairs. Even a relatively small bedroom on the 1st floor would give you more options later on as your family evolves.

Bruce

I don't see the point in spending so much money on a house that doesn't satisfy your needs. Why not sell it and buy a house you like, or tear it down and start over?

Looks like a nice house.

One consideration for extra space would be to make the basement habitable. Meaning it's dug deeper to get 8 or 9' finished ceiling height. And completely waterproofed.

An attached garage will look atrocious. But there may be a way to do a detached garage with a breezeway connecting to the house. Doubtful.

Single story addition on the back may be okay. But doubtful.

Will be a lot less expensive to buy a house that meets your needs than trying to change a dog into a horse.

To make this home a better fit for your needs and preserve the architectural character requires a careful balancing of the floor plan and exterior with your lifestyle needs and budget. You can do a sympathetic addition--one that looks like it was part of the original home--or one is distinctly different.

To get it right, you'll need to engage professionals who do that for a living. You may find a remodeler with in-house design resources that has a great portfolio and track record designing and building additions or you may need to hire an independent residential designer or architect. In either case, I recommend you get both the designer/architect and remodeler to collaborate with you from the outset--that gives you the best opportunity to achieve as many objectives as you can within your budget target.

Best wishes for a successful project.

Don't waste money buying a house that doesn't work. Your envisioned remodel will cost more than you paid for the house. Better to just double your budget from the beginning and buy what you need up front.

It's a beautiful house, and for shure it can take a graceful addition. An architect may suggest the best ways to do it, but what i would advise is having a bedroom on the main floor. With a family, someone at some point will get sick, or break a leg, and since you make the house bigger now, you may as well plan for it. I would not bother with a basement, unless only under the new addition. The cost is simply not worth it, especially if you can have a family room with proper windows with such nice views.