One honored guest at the Sandinista revolution's sixth anniversary celebration this weekend was Mayor Bernard Sanders from Burlington, Vt.

A church ceremony lauding Foreign Minister Miguel d'Escoto and his two-week-old fast for peace was organized by U.S. citizens living in Nicaragua. Their tribute ended with two women, one strumming a guitar, singing a song whose refrain was "Thanks to the Nicaraguans," and with the Americans chanting a Sandinista guerrilla slogan.

Tens of thousands of such Americans have come to visit the revolution here since the Sandinista National Liberation Front took power in 1979. For most, short visits were enough. Others have stayed to live and work for an extended period. Either way, most have made their trip a gesture of solidarity with the Sandinistas and a mark of opposition to U.S. policy toward Nicaragua.

For many, traveling here confirms an already solid belief in what the Sandinistas are trying to do. Working on a coffee plantation for a few weeks as an "internationalist" provides an opportunity to share in concrete expression of an ideal, much as some American Jewish youths find satisfaction working summers on an Israeli kibbutz.

For others, the backpacking "sandalistas," Nicaragua seems to be a way station on a trip back through the 1960s. One Nicaraguan calls these young visitors "totally confused Americans." Although most Americans here perhaps are not so confused, few appear to make critical appraisals of what they see.

As a result, anti-Sandinista Nicaraguans charge that most Americans come here with pro-Sandinista organizations, arrive with a predisposition to like what they see, willingly believe what they are told by their Sandinista hosts and then return to the United States to get out the "truth."

Some cannot wait to get back. Visiting U.S. correspondents frequently have been buttonholed in Managua hotel corridors by "internationalists" with insistent suggestions on how to improve coverage of Nicaragua.

Salomon Alarcon, spokesman for the government's Nicaraguan Committee for Solidarity with Peoples, said such testimony by returned U.S. visitors is an important source of support for Nicaragua in the United States.

"Without neglecting the importance of the rest of the world, we think that solidarity from the North American people has a special role to play," he added. "The visitors are . . . very important, because our objective is not only to have these people pick coffee or build houses, but also to have them inform the U.S. public about our process."

Alarcon said 3,000 Americans visited Nicaragua in 1984 through his organization's contacts with sympathetic U.S. groups. Many more visited through church and political groups without contacting the committee, he said, making the number of visitors impossible to estimate.

Bobbie Camacho, a 35-year-old administrative assistant for a legal services group in the San Francisco area, made her visit to Nicaragua for this year's anniversary celebration in a 15-member delegation from Friends of Nicaraguan Culture. The organization describes itself as a network of "artists, cultural workers, intellectuals, opinion-makers and all people who work with ideas" seeking to generate support for Nicaragua.

"We also support the struggles of the peoples in Central America and the Caribbean," including El Salvador and Cuba, Camacho said as she hurried from the d'Escoto tribute to another event.

However they get here, high-ranking Sandinista officials appear to accord importance to the gestures from U.S. visitors. President Daniel Ortega mentioned Sanders' attendance during his July 19 speech. The government press office sponsored a news conference later that day in which Sanders and several visitors from other countries denounced U.S. policy toward Nicaragua. In its coverage of the July 19 festivities, under the headline "Worldwide Support for the Revolution," the progovernment Nuevo Diario newspaper listed visits by the U.S. and other solidarity groups to Defense Minister Humberto Ortega, then added:

"Debbie Reuben, representative of the network of Solidarity with the Nicaraguan People, which has offices in all states of the North American nation, called being in Nicaragua very important "because at this time when U.S. aggression has been continuing to increase, we consider that the friendship between our two peoples has only increased.' "

In addition to the visitors, several hundred Americans live and work here full time. Activists among them, often joined by visitors passing through, gather Thursday mornings for regular demonstrations in front of the U.S. Embassy to protest U.S. policy toward Nicaragua.

Lin Roth, daughter of a retired U.S. Navy officer, teaches ecology at the Jesuit-run University of Central America and has been here since October 1981. Roth, a 35-year-old Radcliffe graduate, explains her continued stay here as professional satisfaction accompanied by political commitment.

"I've never been anywhere where what you do can count so much," she said. Roth, who played the guitar during the song for D'Escotod'Escoto, said she particularly opposes U.S. funding of the anti-Sandinista contra rebels known as contras who have been fighting to overthrow the Sandinista government for more than three years.

"I think that this is the worst problem here," she added. "The other problems are not going to get solved as long as the aggression goes on. My main responsibility as a U.S. citizen is to speak out against this war."