Exterior changes. Any exterior changes shall be made on the existing foundation unless, in the opinion of the Village of Brewster Board of Trustees, such changes are warranted by the specific circumstances of the particular building. Accessory units shall be located, designed, constructed, landscaped and decorated in such a manner that, to the maximum extent feasible, the appearance of the principal building will remain as one single-family dwelling. No exterior stairway to the second floor shall be permitted at the front of the building. The accessory unit shall only have separate access from the side or rear of the building, except for cases where there is a front entryway with split access inside the building.