Millions of celebrants are expected in New York City for the four-day Statue of Liberty festivities, July 3 to 6. So finding a place to stay -- and to watch the big fireworks show and other major events -- is going to be difficult, although not impossible. But you probably shouldn't delay in making arrangements.

If you are lucky, you have friends living in a Manhattan high-rise with a good Hudson River view who are willing to take you in -- along with all their other out-of-town friends. Get in touch with them now.

Otherwise, you may have to do some phoning to find a vacant hotel room -- or pay a premium price to one of the travel firms that have put together Liberty Weekend packages that include lodging and a choice of options for watching the fireworks and other events.

The situation, which is somewhat complicated, is this:

Accommodations. By now, most of the rooms in New York's biggest hotels already are committed, according to John MacBean, vice president for public relations for the New York Convention & Visitors Bureau. However, this does not mean they are full up.

What has happened, said MacBean, is that a few firms have booked large blocks of rooms and are offering them to the public as part of a weekend package. These packages, described below, tend to be expensive.

But smaller hotels (those with up to about 200 rooms) are still reporting space for the celebration, said MacBean. He suggested contacting a travel agent for help, or you can work the phone to New York yourself. His office can provide information about Liberty Weekend events and a list of hotels. Contact: New York Convention & Visitors Bureau, Dept. SL (for Statue of Liberty), 2 Columbus Circle, New York, N.Y. 10019. Ask specifically for hotel packages.

Liberty Weekend events. There is a fee for some events; others are free; and one -- the July 3 opening ceremonies aboard the aircraft carrier U.S.S. John F. Kennedy -- is by invitation only. Many events require tickets, which are quite limited. These tickets, including reserved seats for the fireworks on July 4 and special big-name sports and entertainment shows on July 6, are being distributed in a lottery. Applications must be submitted by May 1.

Paid events include grandstand seats on July 4 to watch Operation Sail at Battery Park ($60 each) and to view the fireworks at Battery Park ($40 each). OpSail is scheduled all day July 4, from 11 a.m. to 4 p.m.; the Tall Ships will sail the Hudson from the Verrazano Narrows Bridge to the George Washington Bridge. The fireworks in New York harbor -- billed as the largest display ever -- begin at 9:30 p.m.

Two other paid events are the gala closing-night ceremonies on July 6: a 6:30-to-8 p.m. sports salute to Liberty at Byrne Arena in Meadowlands, N.J., featuring ice skater Peggy Fleming and gymnast Mary Lou Retton ($25 each) and a major pop entertainment show at Giants Stadium in Meadowlands (8 to 11 p.m.), where the all-star cast includes Frank Sinatra, Willie Nelson, Elizabeth Taylor and many more ($25 to $200 each).

An information brochure and application for paid events can be obtained by sending $1 for postage to Liberty, P.O. Box 2021, Murray Hill Station, New York, N.Y. 10156-0701. The brochure and applications also are available at Bloomingdale's department stores at White Flint and Tyson's Corner.

For standing-room tickets at Battery Park City Esplanade for Operation Sail, send a postcard with your name and address and the number of tickets you want (no more than six) to: Operation Sail 1986, P.O. Box 2037, Murray Hill Station, New York, N.Y. 10156-0701.

For standing room at the fireworks show: Fireworks, P.O. Box 2034, Murray Hill Station, New York, N.Y. 10156-0701.

For an all-day picnic site at Battery Park City with a view of OpSail and the fireworks: Picnic, P.O. Box 2024, Murray Hill Station, New York, N.Y. 10156-0701.

Of course, Manhattan and the New Jersey shore opposite are full of rooftops, windows and other riverside vantage points where tickets are not required for the fireworks or the Tall Ships parade. Chances are, though, a lot of New Yorkers will beat you to them. Other free events for which no tickets are required include the day-long Harbor Festival New York Fair on July 4, featuring street entertainment, crafts and food throughout lower Manhattan. Also, on the afternoons of July 5 and 6, visitors can tour the Tall Ships at anchor. And on the night of July 5, at 8 p.m., the Great Lawn in Central Park is the site of a free International Classical Concert, with Zubin Mehta conducting the New York Philharmonic and a roster of stars.

For additional information on Liberty Weekend events and tickets: (212) 972-3434.

If you don't want to take a chance on the lottery or spend a lot of time phoning for a hotel room, you may want to consider one of the hotel packages and other options being offered by at least three travel firms. These firms are setting up their own bleachers, have chartered river cruise ships to view the Tall Ships parade and the fireworks and are scheduling special dinner parties with a view -- all for a fee, naturally.

These firms are:

Flagship Travel. The Marblehead, Mass., company claims to have "snapped up the largest room block of any other tour operation in the country." It is offering three-night packages, July 3, 4 and 5, at such hotels as the Waldorf-Astoria, New York Hilton and Marriott Marquis for prices that range from $599 to $699 per person (double occupancy).

That figure includes a reserved bleacher seat along the Manhattan side of the Hudson River on July 4 for Operation Sail; a two-hour cruise around the Statue of Liberty on July 5; and transportation from the hotel to these events.

Options include a July 3 evening cruise during the Statue of Liberty relighting ceremonies at $250 per person and a July 4 fireworks-watching party, buffet and dance at Windows on the World on the 107th floor of the World Trade Center, for $300 per person.

For information on hotel packages: Flagship Travel, 2 Catherine Lane, Marblehead, Mass. 01945, (800) 874-5656. For cruises or the Windows dinner, which can be purchased separately, (800) 322-LADY.sw sk

Travel Tours International. Packages with Travel Tours include air fare from Washington to New York on New York Air, two night's lodging (July 3 and 4) and bleacher seats for Operation Sail (and lunch). Hotels include the Milford Plaza, St. Moritz and Comfort Inn. The price begins at $320 per person, depending on choice of hotels. For information: Travel Tours International, 240 W. 38th St., New York, N.Y. 10018, (800) 824-4109.

ViewPoint International. The firm is offering not so much a package as a choice of options to put together your own Liberty Weekend package.

Among the options: accommodations, beginning at about $110 per person a day; a July 3 buffet dinner dance at the Observation Deck of Windows on the World to view the Liberty relighting ($200 per person); breakfast and lunch on July 4 at Windows on the World to watch Operation Sail ($250 per person); a similar offer at a view restaurant on the New Jersey shore ($200 per person); bleacher seats for Operation Sail and the fireworks ($65 per person); a buffet dinner July 4 at Windows on the World for the fireworks show ($300 per person); and bus transfers from hotel to these events ($25 per person).

For information: ViewPoint International, 1414 Avenue of the Americas, New York, N.Y. 10019, (212) 355-1055.

TRAVEL TALKS: "The Ideal Vacation: Sophisticated Traveler in the '80s" is the subject of an eight-session exploration of vacation travel today offered by the Smithsonian Institution's Resident Associate Program.

Among the travel experts lecturing in the weekly series, beginning April 15, are authors Kate Simon and Stephen Birmingham; Pamela Fiori, editor of Travel and Leisure magazine; and William Penn Mott Jr., director of the National Park Service. The 90-minute programs will be offered Tuesdays at 6 p.m., concluding June 3. The fee is $76 for Resident Associate members and $106 for nonmembers.

For information and registration: (202) 357-3030.