Danish castles; Homes of fairy tale proportions

Not that a smart traveler needs any special incentive to visit Denmark, but 1982 is Castle Year in the land of irresistible pastries and unrivaled shops.

Of the 300-odd castles and manor houses spread across the Danish countryside, 150 will be open to the public this year, and some special castle-rich tours are offered. Freewheeling travelers can plot their own routes as I did early last fall on a weekday ramble no more than an hour's drive north of Copenhagen, an enchanted region where you can't avoid castles even if you try.

Castle country may be done by bus or train with a boating hookup or two, but I went in a car piloted by an old Copenhagen friend named Kurt, whom I sometimes call (not to his face of course) the Great Dane. He has a special and esoteric affection for Denmark, so I seldom question where he leads me.

Slicing inland, he drove to the northwest reaches of Copenhagen, where on a nondescript street lined with sooty brick flats we found the redoubtable and curious Grundtvigs Church, done in 1930s Danish Gothic. It was named for N.F.S. Grundtvig, a 19th-century academician and psalmist, whose work is like the ABCs to every churchgoing Dane. Inside, the stainless steel pipes of a huge organ towered like outsize pens, and a large four-masted model ship hung from the ceiling, a customary Danish churchly adornment.

On the road again, I pointed rather excitedly to a scene that is part of everyday life to the Great Dane. Two black-suited, top-hatted chimney sweeps were in conversation by the side of the road.

''There is a law, said Kurt, that you have to have your chimney cleaned once, I think, a year, but they cannot always find the appropriate costumes anymore. We see ads in the paper for old top hats.''

In the town of Lyngby we passed a long and impressive hedge. Behind it, said Kurt, was Sorgenfri Castle, home to the aunt of Queen Margrethe, its grounds open to the public. At nearby Sollerod, a dreamy village only 10 miles from Copenhagen, we settled in for lunch at the Sollerod Kro, a building of fairy tale proportions, a thatched and rambling structure with snowy stone walls set off by ebony timbers, a shaded courtyard in the center, and a lily pond in front. A kro is an inn, but Sollerod is now exclusively a restaurant, a favorite lunch and dinner destination for Copenhageners not counting their kroner.

There are three small adjoining dining rooms done in hunting, horseback-riding, and farming motifs and a fourth, the Castle Room, that looks out onto Sollerod Castle, a little gem of a place behind a red gate that is owned by a lawyer. The cozy restaurant lounge contains pictures of Danish literary lions, with bits of their writing: Karen Blixen (Isak Dinesen), Soren Kierkegaard with his high forehead and tousled hair, H.C. Andersen, and N.F.S. Grundtvig himself, with flowing white locks. As for the food, it emphasizes nouvelle cuisine but includes certain Danish standbys like biksemad, a cousin of shepherd's pie, the very smell of which summoned childhood memories from Kurt.

After lunch we headed north to Hillerod, site of Frederiksborg, which the G.D. called ''the most fantastic castle in Denmark.'' It had to wait our inspection, though, until a rain squall had passed, the two of us taking cover in a guardhouse while watching puddles in the courtyard reflecting the ages. Frederiksborg, all noble brick ramparts and oxidized green towers and turrets, was built in the early 1600s and rebuilt, after a fire in 1859, along the original plans. It has served for more than a century as the National Historical Museum.

Nearly alone in the castle, we roamed from room to baronial room, mounting a narrow back stairway to the Knights Hall with its grandiose paintings of Danish royalty. Kurt pointed to a 19th-century king on horseback, Christian the 9th, known as the ''Father-in-law of Europe'' because one son was King of Greece; a daughter, Alexandra, married Edward VII; and another was wife to the reactionary Czar Alexander III of Russia.

Frederiksborg's spacious gardens and parkland led all the way to Fredensborg Palace, the royal residence in spring and fall of Queen Margrethe. Her garden, patterned after Versailles, may be strolled at any time, and the palace itself is open to the public in July when the queen repairs to her summer palace in Aarhus or is on the royal yacht in the Danish islands. At other times she is home at Amalienborg Palace in Copenhagen with her French husband, Henrik, or Henri, and their sons, Frederik and Joachim.

Just up the street from Fredensborg Palace is the venerable Store Kro, an inn favored by visiting royalty, important personages, and ordinary Fredensborg trippers. The manager showed me the guest book signed by, among others, Lord Mountbatten, Queen Elizabeth (she signs 'Elizabeth R''), and Dena Kaye, a writer and daughter of Danny Kaye.

Circling back toward Copenhagen we stopped at Skovshoved to see the nicely restored turn-of-the-century Skovshoved Hotel, just a block from the strand, otherwise known as the Danish Riviera. In one of the 20 rooms we looked across thatch and tile roofs all the way to the Swedish coast. The hotel, only five miles from Copenhagen, has a French-like bistro, an adjoining glassed-in terrace , and, on the other side of the building, a sort of Danish pub that serves hearty and inexpensive food.

I stayed in a castle of sorts in Copenhagen, the storied Hotel d'Angleterre, a grand old place with ballustraded balconies, steep mansard roof, and long sidewalk cafe. The d'Angleterre is the choice of diplomats and well-padded businessmen but is not at all stuffy. Coming along a wide, carpeted corridor one morning, I heard a man with a Midwest American voice address his wife: ''You know, the Vikes are playing on Monday night football tonight; I wonder if they'll be on TV here.'' No, even in the land of make-believe and 300 castles, the Minnesota Vikings cannot be found on Danish television. Practical information A 50-page booklet, Danish Castles and Manor Houses, is available from the Danish National Tourist Office, 75 Rockefeller Plaza, New York, N.Y. 10019.