Firstly
Why the limit on how many building you could build? wouldn't it be more logical to have the player simply run out of space, therefore cutting back on the unessential clutter of buildings rather than a cap? I do not even see the purpose of putting a cap on this.
Also I would like to suggest a mini-map to put into one of the corners, so that you don't have to try and scroll around your map which would become really annoyance the more you expand your settlement.
If there are any more suggestions please feel free to expand bellow