The Alaskan frontier, where civilization has only begun to nibble at a beautiful yet sometimes harsh wilderness, is strange and unknown country to most first-time visitors. The state overwhelms, just because it is so huge and so out-of-the-way. Daunted, you may think an escorted tour is the best way to go.

Not necessarily. The state has a somewhat limited but nevertheless quite sophisticated transportation network -- highways, ferries, trains, buses and planes -- that can take independent travelers almost anywhere they want to go. Escorted tours and luxury cruises appeal to many, but if you are an adventurer at heart, you probably will want to see Alaska on your own.

The adventure can begin almost as soon as you leave home. The quickest way to Alaska is by commercial airline, but that certainly is not the most interesting or scenic way.

In the summer, you have several options. You can:

Drive to Alaska via the Alaska Highway through Canada's Yukon Territory.

Board a regularly scheduled bus covering the same route to Anchorage or Fairbanks.

Sail the spectacular Inside Passage on one of the Alaska state ferries.

To see it all, the traveler with plenty of time might consider driving or riding the bus north to Alaska and returning by ferry. (The ferries carry private vehicles.)

Once in Alaska, you can get to most popular destinations in southeastern and south central Alaska -- such as Denali National Park and Kodiak Island -- by bus, train or ferry. Of course, your options increase if you rent a car or recreational vehicle or bring one along. The main intercity highways in the south are paved, although the long-distance roads north from Fairbanks into Arctic tundra country are gravel and some remote spots can be reached only by plane.

Once you've decided to see Alaska on your own, the next step is planning:

When to go. Remember that while most Alaskan public transportation systems operate year-round, departures are most frequent during the summer months because of the influx of tourists. Schedules are cut back substantially or may even be eliminated from fall into spring.

What to take. If you plan to stick to public transportation, consider carrying a backpack, which is easier to tote than a suitcase if you have to walk from a bus or train station to your hotel. A lightweight tent and sleeping bag also may come in handy if lodgings are booked, since you usually can find a convenient campsite.

Getting there. Getting to Alaska can be almost rewarding as actually touring the state. Among the overland or sea options:

By highway: Surprisingly, the approximately 2,300-mile highway route to Alaska from the U.S.-Canada border is open year-round. Most travelers who decide to drive, however, make the trip in the summer when snow is not a threat, and most go by recreational vehicle or van and camp along the way.

By most accounts, the trip should take at least a week. The roads north through Canada to Dawson Creek, the beginning of the Alaska Highway, are excellent. But the Alaska Highway itself can be slow going. Small stretches of it remain in gravel, although most of the way is paved. On gravel sections, you must keep your distance behind vehicles ahead because the dust they kick up can be blinding. On paved areas, you must always be on the alert for potholes.

A brochure called "Driving the Alaska Highway" published by Public Works Canada cautions that travelers "should remember that they are in a wilderness area and that service stations aren't found at every turn in the road." It also warns travelers not to let the gas gauge drop below half full and points out that some stations close early in the evening.

Motels, campgrounds and restaurants are dotted the length of the highway at intervals of 20 to 50 miles, but drivers are advised to make sure their vehicles are in good working condition and to carry a spare tire and fanbelt. In summers, the road is heavily traveled during normal daylight hours so assistance generally is readily available.

Despite the warnings, travelers should not be dissuaded from making the trip. Thousands of tourists make the drive annually, says the Alaska Division of Tourism, "in campers, RVs, cars and even on motorcycles and bicycles."

Travelers can also reach Anchorage and Fairbanks by scheduled bus service. To do so, catch a Greyhound Lines of Canada bus to Dawson Creek and then continue onward over the Alaska Highway to Whitehorse in the Yukon Territory. This service is offered daily Monday through Saturday. In Whitehorse, board a connecting Alaskon Express bus to Anchorage or Fairbanks; this service is available only in the summer, with departures Tuesday and Friday. The one-way bus fare from Vancouver to Fairbanks is about $257. (For more details, see related story, page E1.)

By ferry: The communities on Alaska's southeastern panhandle -- Juneau, Sitka, Petersburg, Wrangell and Ketchikan -- are served only by airlines and the Alaska State Ferry System. No roads reach them from Canada, the rest of Alaska or the lower 48 states. The ferry fleet sails the Inside Passage frequently each month from Bellingham, Wash. (85 miles north of Seattle) or Prince Rupert in British Columbia to Haines and Skagway in Alaska. You continue by bus or auto to Anchorage (750 miles) and Fairbanks (650 miles) or other destinations in Alaska.

The trip from Bellingham to Skagway takes four days, although you may want to stop for a day or two at communities along the way. The tourist fare from Bellingham to Skagway is $218 per person one way. An outside cabin for two is about $200, although you can take passage without a cabin and sleep in the lounge or on deck. Meals are additional. Vehicle rates depend on the size of the vehicle. The bus fare onward to Anchorage or Fairbanks is about $175. The bus trip adds two days to the schedule, and overnight lodging en route is additional.

Reservations for the ferries are advisable, and the earlier the better for summer departures. For information: Alaska Marine Highway, P.O. Box R, Juneau, Alaska 99811-2505, 1-800-642-0066 and (907) 465-3941.

Once you have arrived in Alaska, consider these independent touring possibilities:

Highways: For such a big state -- almost a quarter the size of the rest of the United States -- Alaska has very few miles of intercity roadway. The state's major paved highways link Anchorage, Alaska's largest city, with Denali National Park and Fairbanks to the north and the scenic fishing communities of Whittier, Homer and Seward on the Kenai Peninsula to the south.

Whittier is a departure point for sightseeing cruises of glacier-filled bays. Seward provides access to the ranger-led day hikes at Kenai Fjords National Park and daylong sightseeing cruises in search of wildlife.

Because the roads are so few, as James Wright of the Alaska Tourism Marketing Council notes, "You can't get lost." Alaska's highways, however, offer some of the most magnificent scenery anywhere. The 360-mile George Parks Highway between Anchorage and Fairbanks, for example, yields splendid views of Mount McKinley, at 20,320 feet the highest peak in North America.

The two major cities also are linked by paved highways to Skagway and Haines via Canada's Yukon Territory.

The Dalton Highway north from Fairbanks parallels the trans-Alaska pipeline to Prudhoe Bay on the Arctic Ocean. The road is gravel and is open, but only part way, to tourists looking for a real wilderness drive. "There are no people there," says Wright. "It's miles and miles of mountains and trees and air and animals -- some of the most fabulous country you will see anywhere."

Automobiles and recreational vehicles can be rented easily in Anchorage and Fairbanks, though you should reserve ahead.

Buses: Scheduled intercity bus lines ply the paved roads between Fairbanks, Denali National Park and Anchorage as well as the fishing ports of the Kenai Peninsula south of Anchorage and the ferry ports of Haines and Skagway.

Ferries: The Alaska State Ferry system operates two unlinked ferry networks. One network provides service from Bellingham, Wash., through the Inside Passage to Haines and Skagway (see above). The second serves the mainland ports of southwestern Alaska, including Cordova, Valdez, Whittier, Seward and Homer, as well as Kodiak Island and ports in the Aleutian chain. The 10-hour voyage from Homer to Kodiak Island, departing three times weekly, costs $42 per person. For information: Alaska Marine Highway (see above).

Trains: The comfortable trains of the Alaska Railroad, with viewing domes, operate daily during the summer between Anchorage and Fairbanks via Denali National Park. The trains in either direction depart at 8:30 a.m. and arrive at 8 p.m. The one-way fare is $98, with or without a stopover at Denali.

In addition, there is very scenic daily service south from Anchorage to Seward, departing at 7 a.m. for a four-hour ride. The train leaves Seward on the return leg at 6 p.m. The one-way fare is $30. Reservations are advisable for any of the trains. . For information: Alaska Railroad, Passenger Services Department, P.O. Box 107500, Anchorage, Alaska, 99510, 1-800-544-0552 and (907) 265-2623.

Scheduled air service and charter flights: Many of Alaska's remote communities, such as Nome and Kotzebue on the western coast, can be reached only by air. Alaska Airlines and MarkAir are the major intrastate carriers providing scheduled service. Commuter airlines also serve Kodiak Island and the Aleutian Islands.

Alaska reputedly has more private planes than any other state, many of them float planes capable of landing on interior lakes. A number of them are available for charter. They are used often by wilderness adventurers who want to be flown into remote areas, such as Gates of the Arctic National Park in northern Alaska, to camp, hike, fish and hunt. The planes return for the pickup at a scheduled time.

Charter rates, according to Wright, are based on the number of passengers, length of flight, equipment carried and the flight problems, if any, involved in reaching a remote destination. The price of a flight could be anywhere from $100 to several thousand dollars, he says. To find a charter service, contact the Chamber of Commerce or tourism office in the city or town nearest your ultimate destination.

FOR INFORMATION: The State of Alaska publishes an annual State Vacation Planner that provides substantial information on transportation services as well as lodging, restaurant and sightseeing possibilities. For a copy: Alaska Division of Tourism, P.O. Box E, Juneau, Alaska 99811, (907) 465-2010.

Also extremely useful for independent travelers and anyone planning to drive to Alaska is the 1990 edition of "The Milepost," an annual 586-page, mile-by-mile guide to the Alaska Highway and other Alaskan roads. Included are maps, lists of lodgings and restaurants, sightseeing suggestions and ferry and train schedules. It is published by Alaska Northwest Books of Bothell, Wash. and is available in bookstores for $14.95.