MENTION AN overland trek to some people and they blanch at the thought of backpacking one's food and bedding over a Himalayan pass. But there's a reasonable vacation alternative: a walk from village to village through the European countryside, with meals and a comfortable bed at an inn waiting at the end of each day.

A number of travel firms offer guided walks throughout Europe designed more for the ambler than the hardy climber. On any sightseeing tour of cities and museums, it's an ideal way to break the pace for a few days and get away from tourist crowds. You may even catch a glimpse of a Europe in many ways little changed from the 19th century.

One such tour group, Hiking International Ltd., a British firm, has scheduled several European walks this year, including a ramble through the hills of Tuscany along old mule paths and gravel country roads. In the spring, the 10-day trips coincide with the blossoming of wildflowers; in the fall, with the wine harvest in this part of the Chianti region.

After arrival in Pisa, of Leaning Tower fame, the tour moves on to Volterra, a walled city of Etruscan origins with a commanding hilltop setting. Since ancient times it has profited from its alabaster quarries, and craftsmen continue to produce luminous green and white chess sets and vases. It is from here, on day three, the actual trek begins -- a half-day's walk through pastures and oak woods to San Gimignano, with its medieval fortress towers, described by the brochure as "perhaps the most picturesque and perfectly preserved medieval hill town in central Europe."

Nearby is Certaldo, where Boccaccio lived and is buried, and an optional excursion may be taken there. Along the way is the Romanesque church of Cellole, the setting for PUccini's opera "Sour Angelica."

After a two-day break, the next three days are spent walking through a landscape of farms, villages, vineyards and olive orchards. The trek concludes on the outskirts of Siena, the beautiful and wonderfully preserved city of twisting streets and piazzas spread over red clay hills. Three nights are scheduled in Siena, with time for more hikers in the vicinity. Florence is about an hour away by bus.

All the hikers carries each day is a picnic lunch, a water bottle and maybe a sweater. Luggage is transported ahead. The "Tuscany Trail" walk is graded "1," which means only about half the days on the itinerary are spent walking, and then usually for no more than four hours. The fee of $835 includes all meals and accommodations in inns or hotels. Groups are limited to 15, with departures June 29, Sept. 16, Sept. 19 and Sept. 23. Other treks are scheduled in Italy and elsewhere in Europe throughout the summer and fall.

For more information: Hiking International Ltd., 3 East Saint Helen St., Abingdon, Oxford OX14 5EG, England. For other tour groups, contact the national travel office of the country you are interested in visiting or a travel agent. The British Tourist Authority (680 Fifth Ave., New York, N.Y. 10019) has a fistful of brochures on tours of their walkable islands.

HUNT COUNTRY: Once a year, many of the famous horse-racing and breeding farms in the Virginia Hunt Country of Middleburg and Upperville open up their grounds and stables to the public. It's a rare chance to see what lies at the end of those long driveways winding through rolling green pastures.

This year's self-guided tour, set for all day Saturday and Sunday, May 28-29, includes eight farms, the Middleburg Training Track and the Middleburg Equine Swim Center.

Rokeby, the large estate owned by Mr. and Mrs. Paul Mellon, has been one of the most popular attractions of the vent, which last year drew about 1,400 sightseers. For the first time, Jack Kent Cooke, owner of the Redskins, is opening his new Kent FArm, home for a string of walking horses.

The Hunt Country estates are imposing, but so are the horses. They can be seen from 8 to 10 a.m. both days of the tour working out at the training track, where a light breakfast will be available. They can also be seen each morning at the swim center. At Fox Covert Farm, James Wofford of the U.S. equestrian team will give exhibitiion on his event horses.

Tickets for the tour are $10 per person and may be purchased at participating farms or at the more easily found Upperville Trinity Espicopal Church. A map to the farms is included. The proceeds benefit the church, where a gourmet lunch with Virginia wines (11 a.m.-2 p.m.) will be offered for $6. Each ticket is good for both days, though individual farms can be visited only once.

For information: (703) 592-3343.

STATE GUIDES: To promote its theme, "Nobody Treats You Better Than Georgia," the Georgia Tourist Division is offering a special card that promises a 10 percent discount for a bonus) at 423 motels, hotels, restaurants, gift shops and other tourist facilities in the state. A 48-page book lists the participants. A second, 76-page guide, "This Way to Fun," describing travel attractions, is also available.

Write: Georgia Treat, P.O. Box 1776, Atlanta, Ga. 30301.

To lure the adventure-minded, California has just put out a 40-page brochure listing more than 200 commercial outfitters in the Golden State who offer such guided outdoors activities as hot-air ballooning, soaring, packing (with animals or backpacking), bicycle touring, canoeing, houseboating, sailing, whale watching, wagon-train touring and whitewater-rafting.

Write: California Adventures, California Office of Tourism, 1030 13th St., Suite 200, Sacramento, Calif. 95814. Enclose a large, self-addressed envelope with 37 cents in stamps.

HEALTH AID: Adventurous travelers who strike out from the Third World's standard tourist haunts are wise to determine in advance the possible health hazards and take the necessary precautions.

One valuable free source of information is the International Association for Medical Assistance to Travellers, a 20-year-old nonprofit organization that publishes a series of pamphlets detailing the presence, cause and prevention of several of the underdeveloped world's common but potentially lethal diseases.

Among the pamphlets are those on malaria; schistosomiasis, a parasitic infection that can be contracted by swimming or wading in fresh water ponds in parts of Asia, Africa, the Caribbean and South America; Chagnas' disease, another parasitic infection spread by an insect that breeds in palm trees (and present in thatch roofs) in rural Latin America (hikers beware, warns the association); and the mosquito-borne dengue fever, also a threat in Latin America, Africa and Asia.

Another chart answers that recurrent question, "What shots do I need?" The data on vaccination requirements, says the association, was compiled from the latest World Health Organization studies.

In addition, for any foreign-bound traveler, adventurous or not, the association puts out a regularly updated directory (also free) of North American-trained, English-speaking doctors in 400 cities around the world. The doctors on the list, whether in Algiers, Kyoto or Papeete, have agreed to a standard fee, currently $20 for an office visit; $30 for a hotel call; and $35 for evenings, weekends and local holidays.

Esta Benson of Washington, who travels abroad frequently with her attorney husband, says she has carried the directory with her for years. Two years ago, while in a tropical region of Brazil, she was severely bitten by a swarm of small flies. By the time she reached Brasilia, on Christmas Day, her legs were so swollen she had difficulty standing. She phoned the listed doctor, who not only prescribed a medication that cleared the problem but directed her to a pharmacy open on the holiday.

The association was founded 22 years ago by Vincenzo Marcolongo, a Canadian physician born in Italy who continues as its president. It now has offices in the United States, Canada, Switzerland and Australia handling health inquiries from travelers. Among its goals is acquainting travel agents with health hazards so they may adequately inform their clients.

More recently, the association has completed a package of 24 world climate charts, for which it is asking a $20 (tax exempt) minimum donation. The charts concisely detail monthly patterns, the clothing to be worn and the sanitary conditions of water, food and milk in 1,440 cities.

In Athens in June, for example, the Southern Europe chart informs: The average maximum temperature is 86 degrees; the minimum, 68; the humidity averages 47 percent, and it rains about four days in the month. With that climate, the chart recommends lightweight cotton clothing with a sweater for cool evenings. As for food and drink: Tap water could cause diarrhea to newcomers, so bottled water is advisable in the early weeks of a visit; milk, butter, cheese, yogurt and ice cream are safe; local mean, poultry, seafood, vegetables and fruits are safe.

With the charts in hand, says the association, travelers can safely venture to any country in the world properly prepared.

For more information: 736 Center St., Lewiston, N.Y. 14092 or (716) 754-4883.