Although not exactly a two-parter, The John Cheever Letters follows the tradition of previous Season 4 episodes by harking back to plot elements from the show preceding it. Incidentally, it also follows the tradition of being very, very amusing.
The continuing story is that of the burned cabin, from which only a box of letters - correspondence between Susan's father and famed writer John Cheever - has been saved, making for an awkward first encounter between George and the Rosses (played by Twin Peaks stars Warren Frost and Grace Zabriskie). In other news, Kramer makes a contact for obtaining (illegal) Cuban cigars, and Jerry offends Elaine's assistant with an apparently off-color remark about the woman's underwear. In other words, business as usual.
Once again, the combination of "hot" material (just wait 'til you see how the Cheever subplot pays off) and the right guest stars is an essential ingredient for the episode's success: Frost and Zabriskie, best known for their work with Lynch, are allowed to try something quite different for a change and effortlessly become one of American TV's funniest married couples, with the promise of delivering more of the same in future installments. But one shouldn't forget the regular players. In fact, Jerry's panties remark and subsequent talk with George about women is the usual spot-on gag factory, while Elaine's closing remark is one of the finest in the entire series. No wonder people actually started watching it during this season...