In an effort to avoid the embarrassment of asking Congress for an increase in presidential travel expenses during an election campaign expected to be dominated by talk of economic hardship, the White House is doing some belt-tightening during President Reagan's current California vacation.

The cuts, paralleling those made in government programs by the Reagan administration, have come at the expense of lower-paid staff aides, who have been ordered to double up in hotel rooms during the president's two-week stay at his "ranch in the sky" northwest of Santa Barbara.

High-ranking aides have their usual single rooms.

The doubling up was ordered last week in a memo sent out by deputy chief of staff Michael K. Deaver.

But the real architects of the edict were chief of staff James A. Baker III and White House administrative officer John Rogers.

Deaver pointedly took note of this in the no-love-lost Reagan White House with a postscript to the memo which read, "John Rogers made me do it."

Even less popular among some White House aides than the doubling up was another Rogers decision requiring staff dependents, who formerly traveled at nominal cost on a seat-available basis on the press plane, to pay commercial rates.

In most cases this meant that the dependents didn't make the trip.

Concern with the high style and cost of presidential travel, combined with Reagan's desire to have a real vacation, has forced cancellation of some tentatively planned presidential appearances.

Reagan scrapped a speech scheduled next Thursday before the American Legion Auxiliary in Chicago, the second appearance before a veterans' group he has canceled this month. He decided not to do a fund-raiser the same day for embattled Sen. Orrin G. Hatch (R-Utah).

And he has, at least for the time being, ruled out a Labor Day appearance for Millicent Fenwick, the New Jersey Republican Senate nominee.

The word from Rancho Del Cielo is that Reagan will campaign hard when he starts campaigning--but not before. In otherwords, Republican candidates: Don't call us, we'll call you.

When awards are handed out for tasteless political requests, it will be hard to top the one made by the Arizona Republican official who called the White House the day Nancy Reagan's stepfather, Loyal Davis, died, and asked whether the president would mind addressing a Republican fund-raiser as long as he was going to be in Phoenix for the funeral.

The caller stopped short of suggesting that the president speak from graveside.

In California, veteran Republican strategist Stu Spencer -- political architect of the Reagan victory in 1980 -- is being called in to beef up the ailing campaign of Republican Senate candidate Pete Wilson, whom Reagan will boost at a fund-raiser in Los Angeles tonight on the 20th Century Fox motion picture lot.

Wilson is far ahead in the polls, and Democratic Gov. Edmund G. (Jerry) Brown Jr.'s negatives are sky-high in every survey. But Wilson has run such a wimpy campaign, complete with an ill-advised suggestion that Social Security be made voluntary for those under age 45, that the White House is getting worried . . . . On the other hand, there is growing optimism about the prospects of the California GOP's candidate for governor, George Deukmejian, who won his battle with White House aides to have Reagan do a separate event for him Tuesday night.

Deukmejian nonetheless faces an uphill fight for the governorship against Los Angeles Mayor Tom Bradley. Like Wilson, Bradley has been suffering from campaign management difficulties.

Best line of the week at a White House briefing (which some may find a dubious distinction) came from Conservative Digest's John Lofton, who in midweek unsuccessfully badgered White House deputy press secretary Larry Speakes on the Taiwan issue.

A few moments later Speakes was getting a going-over from a spokesman of the Progressive Labor Party, who was extolling the wisdom of Lyndon LaRouche. "He's here to make me look responsible," cracked Lofton.

A new organization is forming to fight the Reagan tax bill, according to the tongue-in-cheek claim of some of the bill's boosters. It's called "Tax Cheaters Against Reagan".

And when the Reagan motorcade went through a poor Latino section of town as the president left Phoenix the other day, a barber thought he'd drum up some business.

While curious onlookers stared or waved at the motorcade, the barber ran out and held out a sign declaring: "Reag. haircuts $2.75." But the motorcade kept on going.