Betty Ford the author, not to be confused with Betty Ford the dance or Betty Ford the former First Lady, was doing what any media star does upon arriving in Washington: having lunch at San' Souci.

Yesterday, surrounded by several former White House aides and by some of the reporters who covered her, she promptly got down tot the business of updating everybody on Ford family activities since leaving here Jan. 20:

Daughter Susan, she said, has quit her part-time job with the Topeka Capitol Journal to devote full time to her studies at the University of Kansas.

Middle son Jack is looking for an appartment in San Francisco where his job covering environmental/ecological matters for Rolling Stone is taking him.

Eldest son Mike and his wife, Gayle, expect to move to Pittsburgh, following his graduation this spring from theological school in Massachusetts.

Youngest son Steve makes his television debut April 7 on the "Merv Griffin" show, and manages to get Griffin on a horse while he's at it.

To accommodate them all when they do come home, she said her and Jerry Ford's "dream house, reported to cost some $6000,000, soon will be under construction in Palm Springs. At one end with a bath each will be the senior Ford's quarters, at the other near swimming pool and with plenty of space for as yet unborn Ford grandchildren will be "the 'children's' wing."

Promising to take pictures of the groundbreaking in her absence is Ford neighbor-to-be Nicky (Mrs. Leonard) Firestone. Completion is set for January 1978.

Meanwhile, Betty Ford is getting ready for her debut on NBC next year as a television personality in her own right. Besides some "Today" show appearances, she will appear in two programs and will concentrate her efforts mainly on the dance as it applies to the retarded and the handicapped.

She is also starting work on the memoirs which Harper & Row will publish in 1978 and which she will collaborate on with professional writer Chris Chase. She has already begun putting pen to paper when an idea strikes her, as one did in the middle of the night recently.

She was somewhat circumspect on the subject of a Ford in the nation's political future. She would have to "give some thought" to the idea of whether Gerald R. Ford should make another try for the presidency in 1980.

Palm Springs is pretty nice," she said.