Premises tends to mean exactly that... the premises. Which most commonly means the land and the buildings on it. Often it's easiest just to consider the actual land plot's area to be the 'premises'.
n : land and buildings together considered as a place of
business; "bread is baked on the premises"
In short, the external portions of the building, patios, the roof, the parking lot, etc. area all going to be part of the premises of a business.
Kinda begs the question if the guns-in-parking-lots law actually gets to supercede in the case of a liquor license.