QUESTION: I am interested in a trip to the South Pacific that takes in some of the islands that had a part in World War II. I particularly would like to see Guadalcanal and would also like to visit Australia and New Zealand.

ANSWER: Valor Tours (Post Office Box 1617, Sausalito, Calif. 94965; 415-332-7850) specializes in tours of World War II battle sites in the Pacific.For trips that do not take participants to Australia or New Zealand, the company says it can arrange extensions to either or both countries for about $200 a person a day. Prices, given for one person, include round-trip air fare from the West Coast, ground transportation, hotel (two in a room) and some meals.

One trip that may be of interest has been organized for veterans of the 2d Marine Division, though others are invited. The tour leaves Feb. 7, 1991, and goes to Guadalcanal and Tulagi, Auckland, the Bay of Islands, Rotorua, Napier, Palmerston and returns from Wellington on March 1. The cost is $4,380 a person. A group leaves Los Angeles on Feb. 15 and joins the others in Auckland. The cost is $3,230.

A trip to Guadalcanal and Tulagi is set for July 31 to Aug. 10, 1991. The tentative price is $2,900 a person.

A cruise from Rabual - the Japanese stronghold in the Pacific - to Guadalcanal through the Solomon Islands will take place Sept. 1 to Sept. 18, 1991, on the World Discoverer, operated by Society Expeditions. Tentatively, the cost will start at $6,000.

Another cruise will take place Feb. 29 to March 21, 1992 on the Royal Viking Lines' Royal Viking Star. Called the Pacific Memories Cruise, it leaves from Sydney and goes to Noumea (New Caledonia), Espiritu Santo, Guadalcanal, Tulagi, Kula Gulf, Rendova and Plum Pudding Island, Rabaul, Tarawa, Majuro and Honolulu. Feb. 29 to March 21, 1992. The ship will be the Royal Viking Lines's Royal Viking Star. The cost should be $7,000 and up.

The 50th anniversary of the American landings on Guadalcanal and Tulagi is Aug. 7, 1992.

From July 27 to Aug. 8, 1992, there will be a trip to mark the dediction of a Guadalcanal-Solomon Islands War Memorial. The cost is estimated at $3,000. Passengers on a cruise Aug. 2 to Aug. 16, 1992, through the Solomon Island battlefields will also attend the dedication of the memorial.

Using Zodiac boats, cruise participants will go ashore at World War II landing beaches. The cruise cost is estimated at $6,500.

QUESTION: I plan to spend several days in southern New Hampshire this winter. How can I find out about cross-country ski trails?

ANSWER: The New Hampshire Office of Vacation Travel (Post Office Box 856, Concord, N.H. 03301; 603-271-2666) will supply a map indicating downhill and cross-country ski areas and giving their phone numbers, rates and other information.

In season, dialing 800-262-6660 or, in New Hampshire, 800-224-6363, provides a taped message on how many kilometers of trails are open, surface conditions and special events, for at least 10 cross-country areas in the state.

Here are some cross-country areas in southern or south central New Hampshire. All rent equipment and provide lessons at additional cost.

Temple Mountain (800-343-3461 or 603-924-9376), Peterborough, has about 25 miles of trails, about half of which are groomed. About a mile is lighted for night use. The fee is $9 for a full day and $6 for half-day or night skiing.

Boston University Sargent Camp Ski-Touring Center (603-525-3311) in Peterborough maintains about 121/2 miles of groomed trails, and charges $7 for a full day and $6 for a half day.

Windblown Ski Touring (603-878-2869) on State Route 124 in New Ipswich, has about 20 miles of groomed trails, with about half a mile lighted for night skiing. The trail fee is $8.

In Troy, the Inn at East Hill Farm, (800-242-6496 or 603-242-6495), on Mountain Road, has about 10 miles of groomed trails. The trail fee is $4.

Monadnock State Park (603-532-8862) has about 12 miles of hilly, ungroomed trails, best for experienced skiiers. The parking lot is in Jaffrey off of Route 124. There is a $2.50 fee on weekends and holidays.

In New London, Norsk (800-426-6775 or 603-526-4685), east of exit 11 of I-89, has 461/2 miles of groomed trails. The trail fee is $9.50 on weekends and $8 weekdays.

In Grantham, off exit 13 of I-89, the Eastman Community Association (603-863-6772) maintains 131/2 miles of groomed trails. The trail fee is $7.

QUESTION: I have heard there are rattlesnakes on Aruba. Is this true? And are there poisonous sea snakes in the Caribbean?

ANSWER: There are indeed rattlesnakes on Aruba, called, appropriately, Aruba rattlesnakes. The snakes are "dangerously venomous," according to Jonathan Campbell, associate professor of biology at the University of Texas at Arlington and author of "Venomous Reptiles of Latin America" (Cornell University). The snakes, once more numerous, still survive in remote rocky terrain, according to Campbell. The adult Aruba rattlesnake is three or four feet long, smaller than mainland rattlesnakes, and has a faded diamond pattern on a pale gray background. The snakes are generally in the open only at night, as temperatures are too hot for their survival during the day, when they stay under rocks or in crevices. The Aruba rattlesnake - and all venomous snakes - will avoid contact with humans unless they are provoked, according to Dr. Campbell. As in any area with venomous snakes, people should be sure they can see where they place their hands and feet. As for poisonous sea snakes, there are none in the Caribbean, according to Darryl Frost, assistant curator of herpetology of the American Museum of Natural History. Such snakes are found only in the Pacific and Indian Oceans, he said. QUESTION: My daughter is studying in London and is surprised at the cost of food. A friend mentioned a book that described a number of good eating places for 5 pounds or less. Is such a book available? ANSWER: "Nicholson's London Restaurant Guide" (Robert Nicholson) might be what your friend remembers, though the guide's nine-page section on bargain restaurants lists places where a three-course meal is available for 8 pounds or less - roughly $16 at current exchange rates. In other sections of the guide a symbol indicates restaurants that serve meals for less than 10 pounds, or $20. The book is about $7.