In this season the "girls" seem to be moving on from adolescence to adulthood. They are starting to grow up. Adam, especially, is becoming a more mature person (although "I must concentrate on being an actor" phase is a little much). Hannah had a real job working for GQ, Shoshanna is aging from a cute college kid to an annoying young adult, Marnie is becoming the musical one (I see her with a real career in sitcoms after her Peter Pan debut). Jessa is the oldest but also acts the most immature. Still she is the pretty one and the edgy one, the one who is always the center of interest in any scene she is in. One new character who is weird but loveable is Caroline, Adam's sister. Sorry Lena but she is directly out of a Woody Allen Movie.
I guess not wanting to imitate Sex in the City, the summer place scene took place on the North Shore of Long Island rather than the Hampton's. One feature of that episode is we got to see Hannah in a bathing suit.
Editor's note: I wonder if this is product placement for a cellulite removal system.
Young girl's living in New York is one of the standard genres of tv and the movies. Sort of like westerns. In the sixties there was That Girl and Breakfast at Tiffany's. In the 90's and early 00's there was Sex and the City. In the teens there is Girls and Broad City (I don't count Too Broke Girls). To be young, hip, female and living in the city. Us older men have to watch tv to discover what life is like for this trope.