In the hunt for new playwrights, Jack Gilhooley seems to be this winter's favorite. Within a matter of weeks three of his plays will be having their premieres in regional theaters.

Starting previews Feb. 1 to open the following Friday at the Folger is his "Mummer's End," about that traditional New Year's Day Mummers' Parade in his native Philadelphia. A subsequent production is scheduled by Florida's state theaters, Sarasota's Asolo.

Last night the Indiana Repertory Theater presented Gilhooley's "The Brixton Recovery," a study of that London district, where an American prize fighter falls in love with a Jamaican bar maid.

Later next month his "Afternoons in Vegas" will have its world premiere at New Hampshire's Theater-by-the Sea.

Though most theatergoes are wholly unfamiliar with Gilhooley, he's no novice. New York's New Dramatists did his "The Last Christians" and "The Elusive Angel" last season. His "Avenue B" is a spring possibility for New York and NBC-TV has commissioned an original, "The Brothers."

In his early 30s, Gilhooley has taken sabbatical from his bread-earning role as director of theater for Jersey City State College to keep up with his spate of opening nights.

As for the New Playwright's Theater playwright, Ernest Joselovitz, New York's Joseph Papp meant what he said after seeing his "Hagor's Children." The NPT cast, non-professionals all, will be going to Gotham for "Hagar's Children" rehearsals Feb. 14, with an opening aimed sometime in mid-March in the open space of the Public Theater's Martinson Hall.

Papp believes that the play and its production are more important than a set opening night; he didn't unveil "A Chorus Line" for months. NPT's Harry Bagdasian and director Robert Graham Small returned from a visit with Papp and his associates glowing: "Everything will be fixed so that all we do is concentrate on the play."

One playwright who hasn't made it, here at least, is England's 89-year-old Ben Travers, who has had scores of farcical hits at home, but never an American success. Though Baltimore audiences considered it the best of three new plays and though she's sold out in it for a month in Florida, Carol Channing last Saturday wound up her tour in "The Bed Before Yesterday," a London hit since last spring.

Because some 20 critics praised her but knocked the play, the inimitable Channing decided that "Critics are a girl's best friend" and asked producer Arthur Cantor to scrub plans for New York, whose Clive Barnes thought it "a sad little play . . . vulgar without being funny."

Hal Holbrook turned playwright to create his unique "Mark Twain Tonight!" which he'll return to the Opera House stage Feb. 15. Holbrook became a respected Twain scholar to piece his one-man entertainment together. Another player-scholr is Eugenia Rawls, who drew on her role of friend to create "Tallulah!" which she repeats Friday and Saturday at 6 p.m. in the Kennedy Center's Chautaugua Tent. Now comes "Bully" about Teddy Roosevelt, which James Whitmore will open at the National Feb. 14. Jerome Alden uses Roosevelt's words for this, to be staged by Peter Hunt. Still another one-man work is "I Shall Return," with Carl Betz as Gen. Douglas MacArthur in a script by Louis Garfinkle. His opens a tour in Norfolk on MacArthur's birthday, Jan. 26, plays a week in Wilmington starting the 31st and goes on to Boston, Philadelphia, Cleveland and Detroit.

"Grease," considered a frail reed when it began its retrospective on high-school life of the 50s, now is the ninth longest-running show in Broadway history and only recently set a $92,560 gross. It will be back for its third run at the National starting Feb. 1 . . . "A Chorus Line" arrives at Baltimore's New Mechanic Theater Feb. 9; look for the same company, after a Florida fling, at the Kennedy Center sometime this summer . . . Lillian Hellman's "The Autumn Garden" begins previews at Arena Stage on the 27th, with an official opening Feb. 2 under the direction of Martin Fried . . . The Bleecker St. Players are auditioning for Joan Bonoto's "An Arrangement of Words" on Friday from 7 to 9 p.m. and Saturday from 1 to 3 p.m. at Grace Church, Georgetown; performers and technicians are needed; details at 841-0119 . . . "Travesties" has a full Eisenhower schedule this weekend: Friday at 7:30 p.m., Saturday and Sunday at 2 and 7:30 p.m.