Early stages of design – Thoughts – GreenBuildingAdvisor

I am in the design process of my house build in Maine. I am trying to build something I can stay in for 20+ years. 

Here are the early stages of my plans. I am working with an architect on this, just looking for any and all opinions as the process progresses.

I am really interested in green building and I am slightly regretting getting this far as a single level, large foot print house. Hopefully I can justify it to myself by the large lot size and long term plans.  

The exterior is conceptual. The site (11 acres) is almost entirely sloped. It also has ledge. Once a location is finalized, the exterior will be modified. The idea is the garage will be in a lower daylight level. A portion of the driveway will continue up to a first floor level for guest and general use. I am currently thinking full basement in the garage and mechanical/storage space. The rest I would like to do crawl space. 

Here are the changes I have identified that I want so far. 

-Shed some sq footage

-make dining room anywhere but right when you walk in

-open mud room area to main entry

-possible addition of general closet (bathroom, linen, etc.)

-possible elimination of jog in exterior footprint. 

-add mechanical/storage to full foundation. Located to the left as you get to the bottom of the stairs. 

-change shower to tub in common bath

-possibly eliminate tub in master. 

-wish I had an office in this but do not want to add sq ft.