In the flashback we learn that Fran saw Maxwell on TV telling how he almost was about to do "musical with a bunch of people running around dressed as cats." Luckily his secretary Miss Babcock talked him out of it. The musical is, of course, Andrew Lloyd Webber's Cats, which debuted in London on 11 May 1981. Also, The Blue Lagoon (1980) has just been a hit and it is summer, so the flashback must take place in 1980. In the flashback Fran was 16 or 17. So in the actual episode, she is probably 32.
Per the title, a kibbutz is a collective community based on agriculture and practices scientific socialism.