Alice Miller just bought a 35-foot custom-built mobile home to go along with her recently won Mazda RX7, which settled the question of a roof over her head. Now all she needs is a tax shelter.

Miller regularly has siphoned off money from the LPGA Tour this year, collecting four victories, including the Mayflower Classic in Indianapolis Sunday. That title gave her $318,250 so far, which set the all-time LPGA record for single-season money winnings. It should be noted, for the benefit of history, that the season only is half over.

Miller surpassed JoAnne Carner's record of $310,399 set in 1982. But Miller, a 29-year-old who has been on the tour for seven years with fair-to-middling success, has achieved her feat with 18 tournaments and three months remaining and is in position to completely rewrite standards on the tour.

"What a day, what a week, what a year," she said after the Mayflower, which she won by six strokes with a typically consistent closing 70.

In addition to cash flow, Miller is leading the tour in virtually every statistical category. She leads the Mazda Series for finishes in the Top 60, has the low stroke average in competition for the Vare Trophy with a record pace of 70.01, is the runaway points leader for Rolex Player of the Year, and leads in Top 10 finishes and sub-par rounds. It's the kind of year that could set her name in record books next to Babe Didrikson Zaharias and Judy Rankin.

Miller's other victories this year came at the Nabisco-Dinah Shore Classic, the S&H Classic and the McDonald's Classic, which she won with four straight 68s. She also has three second-place finishes and one third, and stands to collect even more money from the various bonuses and incentive earnings offered by sponsors.

Miller has rewritten her career statistics. In seven years on the tour out of Arizona State, she had won only three tournaments and $374,992.

The sudden influx of dollars has thrown the office of San Diego agent-attorney Barry Axelrod into a panic over the client who still has her mother do her taxes.

"Now she's gotten complicated," said Axelrod, who also handles several other LPGA players and a number of baseball players. "The most difficult part is figuring out how to protect her from taxes. But that's a good problem to have, rather than someone who can't pay the bills."

Because of rapidly increasing purses, a trend has developed of one or two golfers dominating the season and occassionally rewriting the money record.

Hall of Famer Carner set the earnings record in 1982 and won the title again in '83, and was the first woman to break the $300,000 mark. Beth Daniel set it in 1980 with $231,000, the first woman to top $200,000, and won the title again in '81. Nancy Lopez led in '78 and '79, setting a record with $197,488 in '78 and breaking it the next year.

But Miller was 11th on the money list last year and seventh in 1983, and is regarded as a consistent rather than a streak player, which makes her thunderclap of a season all the more improbable. Seven-year veterans do not often achieve sudden greatness.

"She's always been consistent, but no big splash, until last year," Axelrod said. "But not many have that kind of consistency, she's been there week after week. So it's been kind of coming on, it's not like it's overnight. She's been grinding away since 1978 and the last two years it's started to pay off."

The turnaround started when Miller's work with Ed Oldfield, a coach who helps a number of LPGA players out of Glen View Golf Club in Illinois, began to show. Her swing has become one of the most dependable on the tour, and she is the seventh-best putter this season.

"I've been working with the same pro for seven years, and he told me it was going to be a long, slow process," she said. "This year, in general, I'm hitting the ball better. My swing has gotten better to where it holds up under pressure. My misses are very playable. I miss it pretty straight for the most part."

Miller's swing faltered in the second round of the Mayflower, when she shot 76 after leading the first round.

She had some of the same trouble on the back nine Sunday, although she said that was from the pressure of all that money, not the tournament.

"I was having a hard time fighting off thinking about breaking the money record and what winning the tournament would mean to me, as opposed to keeping my mind on my game," she said.

The nice thing about becoming suddenly famous and decidedly rich is that you can afford to take a vacation. So when Miller, an incurable baseball fan who wears a Chicago Cubs warmup jacket given to her by Rick Sutcliffe, finally won the Mayflower, that's what she did. In her mobile home. CAPTION: Picture, Alice Miller's 1985 winnings punch in at $318,250 with 18 tournaments left. UPI