Tuftonboro is a nice area. A little remote from 'major' highways, not a problem with true New Englanders.
Find a realtor who is an excellent 'buyer agent'. Not familiar of any in that area but I can ask my contacts. When considering an HOA make sure you know the bylaws, it varies between communities.
I and others have found Benson Woods out of Walpole as an excellent contractor for all your construction planning and needs. The final cost per square foot is lower than if you try doing it alone. Give them a call or check their website.
https://bensonwood.com/
Good luck!