The Rockaway Music and Arts Council held the first of its series of Sunset Picnic Concerts last Sunday night at a new venue - Riis Park. After a year's hiatus, organization president Steve Yaeger told the 175 people in the audience, "We're back," and indeed they are. The first concert at Riis Park (past concerts were held at Fort Tilden) drew a crowd to see the Rockaway Theatre Company perform numbers of its hit production of "Oklahoma." The orchestra played songs from "Oklahoma" as well as old standards. Some of the RTC's "Oklahoma" cast members enjoy the remainder of the show The crowd went home happy. The next concert, honoring former Wave Publisher Leon Locke, will feature Kenny Vance and The Planotones, a doo-wop group.