Special Christmas events in the Brandywine Valley, located where northern Delaware meets southeast Pennsylvania, are featured in a new brochure, ''A Brandywine Christmas.'' Some of the activities are: Yuletide tours through 350 years of American holiday celebrations at Winterthur Museum, Dec. 1-30; Festival of the Trees: decorated Christmas trees with handmade ornaments, Newark, Delaware, Dec.2-3; ''A Christmas Carol,'' by Charles Dickens, presented by the Delaware Theater Company in Wilmington, Dec. 2-19; Hagley's Museum ''Eleutherian Mills:'' the du Ponts' 19th-century country home and 200 acres are decorated for the season and include candlelight tours, Greenville, Del., Dec. 8-29; Candlelight tours of decorated historic homes with paths lit by candles and filled with carolers, Historic New Castle, Dec. 12-13; ''The Nutcracker'' performed by the Academy of Dance at The Playhouse in Wilmington, Dec. 18-19.
Copies of the brochure, including route maps of the area are available by writing: ''Brandywine Christmas,'' Suite 2100, 733 Third Avenue, New York, N.Y. 10017. A Christmas cruise along the Rhine will fill you with holiday spirit in the European tradition. The six-day cruise spends the nights of Dec. 22 and 23 in Strasbourg, capital of the French province of Alsace, and Christmas Eve in Speyer, one of Germany's great cathedral cities.
Christmas trees light Strasbourg street corners and a Christmas market is set up on a medieval square in La Petite France, the oldest section of the city. On the Place Broglie, for three weeks before Christmas, ornaments, creches, Christmas trees, and special cookies and candies are sold.
The cruise, operated by KD German Rhine Line, aboard the MS Deutschland, leaves Cologne the afternoon of Dec. 20, spends the first night in Koblenz, at the confluence of the Rhine and the Moselle, and the next day calls at Gernsheim , where passengers can disembark for an excursion to Heidelberg.
Passengers next visit Mannheim, then arrive in Strasbourg for a two-day stay, then continue on to Speyer on Christmas Eve. Christmas Day is spent cruising the most romantic stretch of the Rhine, as it narrows and winds between steep banks crowned with ruined castles, passes fabled Lorelei Rock, and in late afernoon arrives in St. Goarshausen.
The following day the ship returns to Cologne. On Dec. 27 the MS Deutschland departs again for a six-day New Year's cruise calling at the same ports. Fares for both cruises are $808 to $882. They can be booked through travel agents or the Rhine Cruise Agency, 170 Hamilton Avenue, White Plains, N.Y. 10601, or 323 Geary Street, San Francisco, Calif. 94102. Each year at Christmas the Smithsonian National Museum of American History organizes a ''Trees of Christmas'' exhibition. This year, from Monday, Dec. 21 until Sunday, Jan. 3, twelve 8- and 12-foot trees with decorations representative of various countries will line the museum's central corridors.
Among the themes selected this year are an Armenian Christmas tree created by the Armenian American Society, a calico-and-quilt tree made by the Eastern Shore Piecemakers Quilt Club of Easton, Md., a Swedish red wooden tree, and a Polish Christmas tree from the Polish Arts Club of Washington, D.C. The handmade ornaments range from a complete rendition of the Twelve Days of Christmas in miniature to Scandinavian straw ornaments and colored eggshells. The live trees are complete with root balls so they can be planted outdoors after the holidays. Connecticut is celebrating the Christmas season with thousands of flickering candles, flaring torches, glowing lanterns and twinkling electric bulbs. From Dec. 11 to 23 at Mystic Seaport Museum, hour-long lantern light tours will take visitors through several of the museum's 19th-century ships, homes, and shops. Along the route, visitors discover sailors, ship captains, housewives, and holiday revelers re-creating scenes from Christmases past. Tickets for the lantern light tours are $4 for adults; $2 for children, with groups limited to 15 persons. Advance reservations are essential and should be made early. Call the public affairs office of Mystic Seaport Museum (203) 536-2631.
Over 200 craftpersons will take part in Connecticut's most comprehensive crafts show from December 4 to 6 and 11 to 13 at the Hartford Civic Center. Potters, weavers, glassblowers and wood carvers will display their crafts suitable for holiday gifts.
In addition to displaying their finished wares, many of the exhibitors will hold demonstrations. Admission to the show is $3 for adults, children under 12 free, senior citizens, $1. Hours are Friday noon to 9 p.m., Saturdays 10 a.m. to 9 p.m., Sundays 10 a.m. to 8 p.m. A word to the wise for the Christmas traveler: If you are planning on flying home for the holidays, make your reservation immediately or you may face the real possibility of not being able to get any flight at all. Because of the air controllers' strike, the number of daily flights during the Christmas/New Year's holiday period will be reduced from 14,500 per day to 11,000. And if there is bad weather, there may be longer delays than at normal times.
Other suggestions for the Christmas air traveler: Try to get a nonstop or direct flight to avoid delays due to bad weather; if possible avoid the peak travel days of the Wednesday before Thanksgiving, and Dec. 19-20, 22-24, Jan. 2 and 4; be flexible about the hours you will fly - early morning and late evening flights usually have the greatest number of seats available; get wait-listed on several flights, but do not make actual reservations on several differents flights, preventing other holiday travelers from booking seats.