I’m guessing it’s going to be almost entirely sitcoms simply because of the nature of the format, but what TV show had/has the fewest number of regular locations, i.e. locations that appeared all or nearly every episode?
For example, Cheers occurred, with rare exceptions, entirely inside the bar. Its regular locations were primarily limited to the bar, the office, and the back room. Even the restroom only made relatively infrequent appearances. Of course Cheers had the advantage of being a very large bar, so various places within the same “room” could essentially be used as a separate location.
Family Ties occurred almost entirely in their living room and kitchen, with occasional forays into the bedrooms.
IIRC, Alf occurred almost entirely in the living room, kitchen, and garage.