THE NOVELISTPlay by Howard Fast. Directed by Sam Schacht. At the Theatre Row Theatre through Nov. 3rd. HOWARD FAST calls his new play "A Romantic Portrait of Jane Austen." In a footnote to the excellent production at the Off-Broadway Theatre Row Theatre, Mr. Fast further describes the work as "an invention over which I labored most carefully, endeavoring to create a woman who in thought and speech would not be too far from the original." Austen devotees can decide for themselves. The casual playgoer may well find "The Novelist" a slight but charming piece of romantic hypothesis. The time is 1817, the year of the novelist's passing. Jane (Gretchen Walther) is surprised one fine April morning by the appearance of Capt. Thomas Crighton (Will Lyman) of the Royal Navy. A longtime Austen admirer, the gallant captain explains his intrusion by announcing: "I intend to ask you to marry me." As Crighton presses his suit, Jane's initial annoyance is gradually transformed into an equal ardor. Their spirited debates are both literary and amatory. The Napoleonic Wars divert Crighton for three months, from which he returns "richer by the prize of a French brigantine." But it is already too late. Playwright Fast concludes his story with a poignant epilogue. Under Sam Schacht's admirable direction, Mr. Lyman and Ms. Walther conduct the verbal pas de deux with the grace, eloquence, and wit that it deserves. The strapping Lyman cuts a fine figure as the sailor-suitor. Walther is equally convincing as she portrays Jane's transition from self-possessed independence to heartfelt tenderness. The players are well aided by the handsome production designed by Jane Clark (setting), Kitty Leech (costumes), and Victor En Yu Tan (lighting).