Not too long ago, vacationing in Orange County, Calif., meant packing the kids into the station wagon for a trip to Disneyland, the beach and maybe a couple of nights in a motel.

Plenty of young families still make that legendary pilgrimage. But others with a taste for the high life - and the cash to indulge it - are discovering that Orange County has gone upscale.In 1984, when the Ritz-Carlton Hotel opened along a stretch of oceanfront property in Dana Point, some hotel experts predicted that the luxurious 391-room hotel would never make money. For one thing, it seemed out of character with Southern California. (At first, the hotel required men to wear jackets after sunset; it still requires jackets and ties in the dining room.)

Today, the Ritz-Carlton says it is operating at a profit, and by all accounts, it is a success. It has since been joined by the 350-room Dana Point Resort, which is more modest than the Ritz but nevertheless an upscale establishment on a bluff overlooking Dana Point Harbor.

Now other developers, eager to tap the market for well-heeled travelers, have cleared a variety of environmental hurdles and are planning three giant developments that will forever change stretches of the Orange County coastline.

Within the next four years, nearly 5,000 additional resort hotel rooms will be built along the coast. The construction promises to transform the coastline into an area that the tourism industry, with characteristic boosterism, claims will one day be known around the world as the Orange Coast Riviera.

Developers intend to turn the area into a tourist destination in itself, not just a place to recuperate from day trips to Disneyland, Sea World or Knott's Berry Farm. The new resorts don't plan to compete with nearby inland lodges or with other seaside hotels, but with resorts in Hawaii, Palm Springs, Scottsdale, Ariz., and, yes, even Monte Carlo.

In May, construction will begin on the Monarch Beach Resort, a $300 million, 1,126-room extravaganza on one of the last untouched strips of land along Coast Highway just north of the Ritz-Carlton in Dana Point. The developers of the ocean-bluff proj-ect are spending nearly $20 million on landscaping alone.

Later this year, construction is scheduled to begin on a four-hotel 1,450-room development on 20 acres along Pacific Coast Highway in Huntington Beach called The Waterfront.

And by 1990, the Irvine Co. plans to begin construction on the first of three hotels with a total of 2,150 rooms and two 18-hole golf courses on one of the choicest pieces of real estate in Southern California, a three-mile strip of rolling hills between Laguna Beach and Corona Del Mar called the Irvine Coast.

Despite a general slump in the Orange County hotel market, developers are confident there will be enough tourists to back up this unprecedented building spree. Some assert that demand for these huge seaside resorts has gone unmet for years. Others say that even if adequate demand does not yet exist, it can be created with savvy marketing.

"Resort development is hot across the country. People are taking more vacations. Travel is up, and more foreigners are coming here," said James Burba of Pannell Kerr Forster, a consulting company serving the hotel industry.

"The Ritz opened everyone's mind to the idea that here is a real resort area," said Sherrie Laveroni, general manager of the Dana Point Resort. "It put Laguna Niguel on the map."

The Ritz-Carlton, jointly owned by Prudential Insurance Co. of America and Atlanta-based W.B. Properties, Inc., billed itself as the first major resort built along the Southern California coast in nearly 30 years.

Besides its seaside locale, the $100 million project boasts tennis courts, swimming pools, meticulous service, and a collection of 18th century art on its walls. The hotel has won five stars - the highest award _ from both the Mobil Travel Guide and the American Automobile Association, two of the more prestigious honors in the U.S. travel industry.

Its look and feel have been compared to opulent turn-of-the-century seaside resorts. But its rates are definitely modern day, with rooms starting at $185 a night and going up to $2,000 for a five-bedroom suite with a baby grand piano.

Can Orange County _ once considered a byword for provincialism in some circles _ draw the same well-heeled travelers who patronize resorts like Palm Springs?

Industry experts say the jury's still out. A lot depends on whether the new hotels scheduled for construction live up to their billing and are snazzy enough to complement the Ritz-Carlton.

According to general manager Schielein, the Ritz-Carlton's reputation is drawing a steady stream of vacationers from Europe and Japan. But Schielein acknowledges that virtually all of the Ritz-Carlton's weekend guests are Californians. Even of those who sign on for longer stays, most hail from California or other Western states.

"The Orange County coast's greatest asset is that it is adjacent to a nearly 14 million-person market in Southern California, and the Northern California market is certainly available to it," said Sam L. Van Landingham, a partner with Portman Properties, a Atlanta development company that has built posh hotels from New York to San Francisco and the Far East.

"How successful (the Ritz-Carlton) will be on an international or national basis is harder to determine," Landingham said. "It doesn't have a year-round climate, like Hawaii, so it's not a true year-round ocean resort."