Sometimes planning a trip abroad can seem a daunting task, especially if you want to travel on your own -- no guided motor-coach tour -- to a place off the standard itinerary. Such as Eastern Europe.

A recent letter from a Virginia woman, interested in visiting her deceased father's home town in Poland, illustrates one of the most common problems: Where do you get good planning information? She had tried writing directly to various offices in Poland with no success.

Among her concerns: What is the cheapest air fare? How can she get from Warsaw to the town of Suwaki, 90 miles to the northeast, where her father lived? Is there visitor lodging in the town? Is there a cheaper alternative to hotels and motels in Poland? Is such a trip feasible, since she doesn't speak the language?

She was, her letter suggested, inexperienced in travel -- certainly it will be her first visit to Poland -- and she was asking for advice. But even seasoned travelers seek answers to the same sort of questions.

It is unrealistic to expect to find detailed answers to every travel question in advance, especially when the trip is to a foreign destination. Sometimes you must leave home with uncertainties unresolved, simply trusting that everything will turn out well.

But there are practical steps to get answers to most questions before you depart, and the kinds of information sources available to the Poland-bound correspondent are much the same as those available to travelers planning a journey almost anywhere.

Here's how she, or anyone, can go about gathering the necessary information to plan a trip (not necessarily following the steps in this order):

* Buy or borrow a good guidebook: If it is your first visit to a new country, find a basic guidebook that is as strong on "getting around" details as it is on "what to see and do." For the Virginia letter writer, Fodor's "Eastern Europe 1985" ($15.95) is such a book.

Fodor's is one of the standard guidebook series, and copies should be available in most good bookstores. If not, they can be easily ordered. (Nagel's, another series, has a volume on Poland alone, but for $38.) In a three-page description of the attractions of Poland's northeast, Fodor's lists two lodgings in Suwaki, an inexpensive hotel and a motel, with addresses included.

Because some countries are rarely visited, few guidebooks have been published about them. A good source for what's in print are three East Coast bookstores specializing in travel:

Travel Books Unlimited, 4931 Cordell Ave., Bethesda, Md. 20814, (301) 951-8533.

The Complete Traveler Bookstore, 199 Madison Ave., New York, N.Y. 10016, (212) 685-9007.

Traveller's Bookstore, 22 West 52nd St., New York, N.Y. 10019, (212) 664-0995.

* Contact the national tourist office of the country you plan to visit: Most countries welcoming tourists, including Poland and other East European nations, have such an office, usually in New York City. The country's embassy in Washington should be able to provide the address. The Polish National Tourist Office, called Orbis, is at 500 Fifth Ave., New York, N.Y. 10110, (212) 391-0844.

An Orbis spokesman supplied the information that the best way to get from Warsaw to Suwaki is by bus, about a five-hour trip. He added that Poland's northeast is an area of lakes and rivers looking a lot like Finland and "very beautiful in the summer." He named two Orbis-run resort hotels in the vicinity (but none in Suwaki) for which he could book reservations.

Other helpful information: He provided the names of the airlines making New York-to-Warsaw flights and the approximate cost ($899 round trip in the summer on an Apex discount fare; $749 until May 14).

Also, he said, Lot, the Polish airline, will be flying charters this summer for about $100 less from U.S. cites with large Polish populations, including Chicago, Detroit, Boston and Hartford. A list of flights will be available in February from the tourist office.

* Find a travel agent specializing in the country or area of your visit: This isn't always easy to do, but it can be worthwhile to spend some time searching. Unfortunately, the American Society of Travel Agents does not list travel agents by specialty.

Some agents advertise a speciality in the Yellow Pages. Sometimes the national tourist office will provide the name of an agent. Phone the travel agents in your community, and ask for a reference.

A Washington reference provided the name of Jonathan Chase, manager of the Eastern European department of Security Travel, 1631 Washington Plaza, Reston, Va. 22090, (703) 471-1900. Chase, who speaks Russian, has visited the Soviet Union many times, he says, although he has been to Poland only once. However, he has arranged many trips there and is in frequent contact with the Polish National Tourist Office.

He supplied details on Poland's complicated currency regulations and also the useful fact that Poland operates an extensive -- and inexpensive -- Youth Hostel program. Polish hostels are open to travelers of all ages possessing a hostel membership card ($20 from any office of American Youth Hostels, which also offers a directory to international hostels).

* Be creative in your information search: Check the library for newspaper and magazine articles on travel to your planned destination. Try to talk to people who have been to the country or have an interest in it. Phone the national airline, if there is one.

Sources for Poland might include the Eastern European language or history departments of a major university; Polish-American societies; the tour desks of airlines flying to Poland (among them Swissair). The Map Store at 1636 I St. NW sells Bartholomew's English-language map "Europe, Eastern" for $6.95.

The Virginia letter writer has one other concern -- the language. How easy will it be for her to travel on her own speaking only a very little of the language?

Certainly outside Warsaw and Poland's other large cities the lack of Polish will prove difficult, says Jonathan Chase. But adventurous travelers generally do not let this inhibit their itinerary.

First, it is always helpful to obtain a phrase book and tape cassettes to practice simple tourist inquiries. Both are available in Polish. The Globe Book Shop and Foreign Language Center at 17th Street and Pennsylvania Avenue NW, for example, stocks the Berlitz "Polish for Travelers" ($4.95) and Conversa-Phone's 20 Polish lessons on tape ($11.98).

You don't have to speak complete sentences: "One ticket for Suwaki" (practiced a couple of times) should give the bus clerk an idea of what you want. If not, point out the words in the phrase book.

Obviously, the better prepared you are, the less apprehensive you will be in venturing away from an escorted tour. Whatever remaining questions you have may be answered as soon as your flight arrives.

Find the local tourist office, if there is one. Orbis has service bureaus in the international hotels, where usually you can find someone who speaks English. Or you could catch a taxi to the U.S. (or British, or Canadian) embassies, where you are likely to find someone who knows his or her way around the country and is willing to help.