This hardly seems the right moment for a period musical, particularly one with so much book trouble. A bodacious, bawdacious leg show would be more in keeping with the times. In any case, "Away We Go" is an operetta, pure and simple, at its best, witty and charming, and at its worst, prime for a severe blue-pencilling. Not knowing Lynn Riggs' "Green Grow the Lilacs," the basis of the libretto, one cannot vouch for the faithfulness of the adaptation, only for its unevenness and absurdity.

No two period operettas ever seem to be set in the same locality at the same time, probably because the plots are all too similar. This time it's Oklahoma, just after the turn of the century, but the picturesqueness of the epoch is a saving grace, when not spread on too thickly.

The hero and heroine are thoroughly drab; the comic characters are far more interesting. The villain dominates the proceedings, but it is doubtful whether he is a serious or a comic character. One moment he is a brutal, psychopathic murderer who keeps pictures of nekkid women on his walls. The next moment, the best sequence in the show, he is made fun of in a riotous song. "Pore Jud Gray Is Dead." Two minutes after Jud has accidentally killed himself in a fight with the hero, the lovers ride off singing the hit song, "Oh, What a Beautiful Morning."

The big surprise comes from Richard Rodgers, who invades the domain which used to be the exclusive property of Jerome Kern and Sigmund Romberg. Instead of his usual racy tomfoolery and querulous laments, Rodgers has turned out a score that would be superb if it didn't sound as if it were from Kern's own pen.

Particularly noteworthy are the dances by Agnes de Mille, which, excepting for an occasional balling gesture, are among the finest ever seen in a musical. The cast is capable, especially Celeste Holm, whose comic touch is deft, and Joseph Buloff, whose comic touch is broad. Lee Dixon is fairly well known, but he is distinctly handicapped by lack of material and his resemblance to Red Skelton.

Oscar Hammerstein deserves a rose crossed with a scallion for his superb lyrics and clumsy adaptation. The Theater Guild deserves a loud cheer for beating the Shuberts at their own forte.