Dinner theater has escaped the exurbs, bringing Great American myth spun of Kansas corn silks, to the Kennedy Center's Terrace Theater. "An Evening with Rodgers & Hammerstein & Lerner & Loewe" -- not to mention Burton Lane who collaborated on some of the music -- makes for a low-risk outing guaranteed not to shock or suprise. The fare is good old show tunes and schmaltzy deja vu: "June Is Bustin' Out All Over" melds with "Hello, Young Lovers" meets "Shall We Dance" marries "Wouldn't It Be Loverly." And we don't stop there. We go round the globe -- from "South Pacific" to ''Oklahoma!" from "Brigadoon" to "Camelot" -- taking a nostalgic and sexist look at life, love and cosmic causality. It's the way we thought we were. And the way we think we ought to be. In all, it's about two hours of tuneful time- traveling with a cast composed of Orkin Man-lookalike Steve Elmore, Laura Waterbury, Martin Vidnovic, Elizabeth King and Marni Nixon. Of the five, Vidnovic and Waterbury were most appealing, with the former particularly eloquent during the soliloquy, "Lonely Room" from "Oklahoma!" And it is mighty fine when the two get together for an energetic and humorous duet called "How Could You Believe Me?" The evening also brings to light the real- life form of unsung heroine Marni Nixon, whose dubbing made melodious the cinematic voices of Deborah Kerr in "The King and I," Audrey Hepburn in "My Fair Lady" and Natalie Wood in "West Side Story." The production, originally two entities staged for cabaret at the St. Regis King Cole Room in New York, seems less than enough for the Terrace Theater, small though that arena may be. It is "An Evening" without narrative or motion, more a recital than a revival. The performers are stranded, wooden and isolated, on a strange stage despite the comforting presence of on-stage pianists in tandem. It's rather like watching the whole thing from Merv Griffin's green room. Not a word is spoken. Not a toe is tapped. The parts are separate from the whole and seem to suffer from that. Though, all in all, fans of this limelighted quartet may proceed KenCen- ward with $12.50 and cockeyed optimism. AN EVENING WITH RODGERS & HAMMERSTEIN & LERNER & LOEWE -- at the Terrace Theater through November 15.