Notes on a Voyage to Once-Forbidden Vietnam : With the ban on American travel lifted, four U.S.-based lines now offer trips.

“Sneaking into Hanoi” is how one California man facetiously described our clumsy convoy of mini-buses led by a horn-blowing, siren-sounding police escort as we bounced along the rough, potholed highway. From the lines of bicyclists along the roadway and the bent-over farmers in the rice paddies, startled faces framed by conical straw hats or khaki topees turned to stare.

It takes three hours to cover the 60 miles on National Highway 5 from the port of Haiphong through the Red River Delta into the capital city of Hanoi. Along most of the route a railroad parallels the highway, and at one point, pedestrians, bicyclists, motorcyclists, trucks and buses share a one-way bridge with trains. The trains have the right of way.

We were among 120 passengers--a mix of Americans, Canadians, Germans, Austrians and Japanese--on SeaQuest Cruises’ expedition ship Frontier Spirit on a cruise to Vietnam in November. This cruise was one of the first to be scheduled and marketed in the United States since the ban on American tourism to Vietnam was lifted last December. Other U.S.-based cruise lines currently offering 1993 cruises to Vietnam are Pearl Cruises, Classical Cruises and Royal Viking Line.

Our 16-passenger mini-buses were neatly labeled Bus A through Bus H, and they were not permitted at any point to get out of alphabetical order.

We passed dusty trucks and lumbering rusty buses overloaded with passengers, their parcels and animals tied on top. Market-bound bicyclists pedaled past with strings of live ducks dangling from their handlebars, or pink pigs fastened into woven baskets tied to the back seat, their black snouts stuck out of the mesh.

Along the roadside, women trotted by with bamboo yokes and baskets filled with bok choy, mandarin oranges and live chickens. Children tended the water buffalo, which grazed in the fields or beside the road.

It was the beginning of the rice harvest, and farmers put the stalks of rice out on the roadway so that the passing traffic could thresh it. In the golden green paddies, two women working in unison swung a bucket rhythmically to slosh water from the irrigation ditches onto the fields. Flocks of ducks paddled in the water.

In Hanoi, we were taken first to Ho Chi Minh’s Mausoleum, a square, fortified-looking building on a wide boulevard with parkland and government buildings around. The guides cautioned us--that no one was permitted to take bags or cameras inside, to wear hats, shorts or tank tops, or to keep their hands in their pockets.

We filed in in orderly rows, two-by-two up a stairway covered in red plastic, past Vietnamese soldiers standing rigidly at attention. The body, encased in its glass dome, looked eerily asleep in the warm lighting. The famous wispy white beard and thinning white hair were neatly combed, and the hands resting against the severe black suit were slightly curled like a pianist getting ready to play.

In the same area as the Mausoleum were the 1906 governor’s palace, Ho’s simple wooden stilt house by the lake, and the One Pillar Pagoda, built in 1049 and rebuilt after being destroyed by French armed forces in 1954. The excursion also includes visits to the Museum of Fine Arts, the Temple of Literature with its temple dedicated to Confucius, and the Army Museum.

A catered lunch, its spiciness toned down for Western palates, was served in a gallery of the elaborate opera house, followed by a program of Vietnamese folk music and dance.

We had entered Vietnam through the Gulf of Tonkin, and on the first day sailed into an anchorage in Ha Long Bay for sightseeing boat tours through the jagged-rock islands reminiscent of the more famous mountains in Guilin, China.

Curious fishermen came to look at the Frontier Spirit in the bay, its gleaming white, red and blue standing out against rusty Vietnamese and Romanian cargo ships.

As we sailed farther south, first to Da Nang with an excursion to the old dynastic capital of Hue, then to the tourist town of Nha Trang, the towns and villages became more modern and prosperous until we finally reached Ho Chi Minh City (the former Saigon), which after Hanoi looked as bustling and Western as Hong Kong. It was the only city we saw with modern, first-class hotels.

It seemed to us that traveling aboard a cruise ship on a group visa must be the simplest and most comfortable way to see the country. The Vietnamese government frowns on travel by individual tourists, except for businessmen looking for joint-venture investments.

The 164-passenger Frontier Spirit was built in Finland in 1990 and contains all the latest environmentally friendly equipment, from a water treatment plant to grinders that reduce broken glass to sand-sized fragments that can be released back into the sea. An incinerator gets rid of burnable garbage, and non-recyclable food garbage is stored in a freezer until it can be disposed of ashore.

Cabins are all outsides, some with private verandas and all with twin beds that can be made into a queen-sized bed. The food, prepared by an Austrian chef, is good to excellent, and a simple cabin service menu is available 24 hours a day. The Frontier Spirit features a musical trio that plays for dancing before and after dinner, as well as during teatime.

Upcoming 1993 cruises to Vietnam aboard the ship include 22-day Vietnam and China land/cruise packages departing the United States April 11 and Aug. 28, and April 9, 1994, calling at all the above ports plus the Chinese cities of Zhanjiang, Xiamen, Fuzhou and Shanghai. Two 18-day “Ancient Vietnam” land/cruise programs are also offered from Hong Kong to Singapore, including the above ports plus Kuantan, Malaysia, on June 2 and Oct. 19.

Money-saving “explorer rates” of $2,930-$3,970 per person, double occupancy, are available for a minimum of five cabins on each cruise. The available cabins are assigned 30 days ahead of sailing time, with the highest-category cabins going to the earliest reservations. A $500 non-refundable, non-transferable deposit is required, and final payment is due at least 90 days before departure. Shore excursions during the cruise are included; air fare and pre- and post-cruise land programs are not.

Regular brochure fares range from $5,800 to $12,900, including all shore excursions, land programs at the ports of embarkation and disembarkation, and air fare from Los Angeles, San Francisco or Seattle.

Other vessels calling at Vietnamese ports in 1993 include Pearl Cruises’ 480-passenger Ocean Pearl, offering two 19-day Vietnam itineraries from Singapore with package departures from the United States on March 4 and Aug. 23. The ship calls at Ho Chi Minh City during the March 16, July 12 an Oct. 14 departures on the “Great Cities of Asia” itineraries. Fares range $3,550-$8,250 per person, double occupancy, plus air add-ons of $695 from the West Coast.

Classical Cruises’ 80-passenger Aurora I has scheduled 16- and 17-day Vietnam cruises, with an optional extension to Angkor Wat for Dec. 23, 1992-Jan. 7, 1993; Jan. 3-19; Jan. 30-Feb. 16; Feb. 9-26 and Feb. 21-March 1, priced $4,495-$5,995 per person, double occupancy, excluding air fare. Pulitzer Prize-winning author Neil Sheehan, former New York Times correspondent in Saigon, heads the roster of shipboard lecturers on the Jan. 3 sailing.

Royal Viking Line’s Royal Viking Sun will make a maiden call at Ho Chi Minh City on its world cruise this winter, Feb. 4-5. A 43-day segment, including Ho Chi Minh City, leaves Hong Kong Jan. 31 and costs from $15,695 per person, double occupancy, including air fare and a free three-night land package in Hong Kong. An optional overland tour to Angkor Wat, leaving Bangkok Feb. 8 and meeting the ship in Singapore Feb. 11, is also available for about $2,500 per person, all-inclusive, for single or double occupancy.

In addition, the elegant little (200-passenger capacity) Royal Viking Queen will call at Ho Chi Minh City during two Hong Kong-to-Singapore 13-day cruises, departing Jan. 25 and Feb. 20. Prices start at $9,995 per person, double, including air fare from the West Coast.

For free brochures, contact a travel agent or SeaQuest Cruises at (800) 223-5688; Pearl Cruises at (800) 556-8850; Classical Cruises at (800) 252-7745, Ext. 10, and Royal Viking Line at (800) 422-8000.