There are no palm trees in South Dakota and hardly any Communists. Still, the distance between Mt. Rushmore and Carlos Marx is not nearly as great as the hostile past would suggest.

A planeload of curious South Dakotans, friendly but skeptical, established this for themselves last week - the doubleknit gentry from the west prairie checking out the Revolution. They invaded Cuba with their two U.S. senators, dropped a couple of basketball games and discovered taht the Nuevo Hombre Cubano is, well, just folks.

"This is the largest group of Americans to be down here since the Bay of Pigs," Sen. James Abourezk dead-panned to a Cuban-American banquet audience. "And, frankly, we like the welcome a lot better this time."

The Cubans waited for the traslation before laughing.

A Havan newsboy, according to a Canadian diplomat, was hawking his newspapers a few weeks earlier with this provocative come-on: "The Yankees are coming!"

Those words still carry a certain freight in Cuba, where people are preparing to celebrate on April 17 the 16th anniversary of the victory at Giron (we call it the Bay of Pigs) and Defense Minister Raul Castro complains to the senators about U.S. spy planes harassing Cuba with sonic booms.

But the Cuban greeting was expressed most directly, and sweetly by nursery school children waving and chanting from a balcony: "Rie conmi-go, ri-e con-mi-go!" Laugh with me.

So the Dakotans proceeded to explore this western outpost of communism with the same amiable directness, wisecracks and occasional grossness that have endeared. American touriss to the rest of the world.

They took a million snapshots (every gringo has a little flash camera, it seems) and threw bubblegum to school children and passed out Mt. Rushmore posters and joked about the anti-imperialist slogans, the only billboards in town.

"We don't feel much like imperialists," said Bob Dezonia, president of the University of South Dakota. "In fact, South Dakota is 50th on so many indicates, it's probably the least imperialist state of all."

Stan Marshall, athletic director at South Dakota State, compared Cuba's 8 million citizens to South Dakota's 600,000: "They got more people than that down here waiting for buses. They got South Dakota waiting for buses and North Dakota riding them."

Several of the South Dakota men pulled aside a veteran news photographer, who has visited Cuba many times before, and asked him an age-old question, a preoccupation of American males touring Havana in the old days before Castro: "Where do you go to get laid?"

The photographer told them: "Miami."

Still, there was a political message in their visit that perhaps reveals more about America than Cuba: If an orthodonist from Rapid City and a juke-box operator from Yankton and a cattle man from Murdo think it is silly for th United States to continue its embargo of Cuba, then perhaps it is not too soon for U.S. politicians and diplomats to normalize relations.

"It makes all sorts of sense to me," said Dr. Gordon Magnusson, a conservative dentist who seemed to be more agitated about sitting next to The Washington Post on the tour bus. "If we recognize the Soviet Union and China, we certainly should recognize what's 90 miles off our shore."

Magnusson, like so many others who saw the new schools and factories and housing, retains considerable doubts about the advantages of Marxism and a closed society, but his conclusions were scrupulously fairminded:

"I'm happy that they're enthusiastic and pleased with the way thins are going. It's entirely possible that things were intolerable under Batista. I've been told that our government was extremely hard on Castro at the time when he needed help and he could have wound up on our side. The fact that he is Communist now probably reflects poorly on our State Department."

For one thing, the South Dakotans were pleasantly surprised to find that the Cuban ideology intersects with their own values on some things. When they head the minister of education extolling the educational value of work, explaining how all Cuban children are expected to do productive work in the fields in addition to their studies, it did not sound so alien from what South Dakota children learn on the Farm.

At a rural boarding school for junior high children, the Americans were frankly impressed when they saw the crisp order of the place - boys and girls wearing neat uniforms with little blue neckties standing respectfully at attention, taking copious notes on their physics and chemistry lectures.

Arnie Bauer, a junior high principal from Sioux Falls, exclaimed: "All I can say is - gracious! We had the dress code taken away from us years ago by the Supreme Court. That's the first thing you got to do - to take control of the kids before you can teach."

The contrast with discipline in American junior high schools had the tourists buzzing. Bauer asked the assistant principal, Gilberto Lirio: "What do you do all day if you don't have any disclpline problems?" Lirio, missing the humor of the question, responded with some standard rhetoric about the formation of new habits for the "nuevo pueblo."

The South Dakotans and their basketball team (actually a mix of players from the two state universities were invited to Cuba because their two senators - Abourezk and George McGovern - have both been far out front in espousing normal relations with Cuba, notwithstanding the natural conservatism of their state.

McGovern was the first U.S. official to visit here two years ago; Abourezk has made four trips to the island, (Cuba, says Abourezk, is one place where a U.S. senator can take a vacation without being pestered by flunkies from the American embassy).

Back home, the ball players and their parents and the other curious ones who signed up for the trip got "a little heat" from some of their neighbors - "for doing dirty work for the COmmies." But, as Dave Geisler of Murdo put it, "I'm not listening to any of that crap. This is historical."

South Dakota State got a few letters of complaint, said athletic director Stan Marshall, but he brushed them off and added:

"One little old lady wrote me and said she didn't mind the team going to Cuba, but she didn't want them to go anywhere with Abourezk."

A few words about the basketball game, the ostensible purpose of he trip.The Americans palyed valiantly and the Cubans played expertly and the 15,000 spectators applauded the visitors generously (as they were to told to do, according to one party member).

The Cubans won both games by exactly 19 points which left some South Dakotans with an [WORD ILLEGIBLE] feeling and cost NBC Correspondent Richard Valeriani a box of Cuban cigars. He bet on Cuba the second night and gave 20 points to Dan Parrish from Murdom, who says he is a professional gambler, among other things, back home.

The high point was the opening ceermony before the first game, when the blond young Americans boy came marching in, carrying U.S. and South Dakota flags. They paraded around the arena to the hunderous and rhythmic applause of the Cuban fans. Sixteen years ago this area, called Sports City, was where the Bay of Pigs prisoners were put on trial.

Sam Milanovich, an assistant coach from Dakota State, was walking through downtown Havana when a Cuban came up and offered him 50 pesons - equivalent to $69 or so - for his shoes. "I'm surprised Sam didn't take it," quipped Doug Martin, another coach.

When the Americans went shopping at the downtown boutiques set aside for foreign tourists, they were frequently "hustled" by Cubans who asked them to take their pesos and go into the shops and buy them items not available to Cubans generally.

Dr. Magnusson looked over the skimpy goods on sale in tourist shops and remarked: "I've been to rummage sales back home that had more variety."

In short, the South Dakotans saw cleary enough that they were visiting a country where scarcity is still enormous, where food and other goods are rationed and the rigid bureaucratic controls produced grumbling.

The tourists saw the grace of the old cities, the oleander blooming by Lenin Park and the Royal Palms set in Spanish courtyards and "Christ of Havana," erected by the dictator Batista, looking down now upon two Soviet freighters.

And, of course, they saw the poverty, thatched roofs in the country-side, tiny stucco cabanas in the city - not very different, some of them observed, from other Carribean islands where they have visited. Jim Burt, a sportscaster for KELO-Land TV in Sioux Falls, tried to be fair about it.

"This housing really depresses me," Burt said. "But then I've never seen the slums of New York."

In muted ways, they also encountered the repressive qualities of Cuban socialism, the relentless boosterism of their tour guides versus an occasional counter-revolutionary wisecrack from other citizens.

One party member privately joked about the austerity of Soviet movies:

"There is only one plot for Russian movies. They all go on a train. Everybody is scratching themselves. An old lady produces some black bread, so hard they can't eat it. The lady's tears soften the bread. Then a bomb blows up the train. But it is a happy ending - because of the lives they had."

On the beach one afternoon, Mike Imig met a baseball freak, a Cuban who follows U.S. baseball so closely that he knew that Ken Griffey of the Cincinnati Reds once played minorleague ball for Sioux Falls.

"He told me," Mike said, "the only place he can talk freely is on the beach."

One day at lunch, the two senators and Rep. Les Aspin (D-Wis.) and other guests were given a spirited replay of the victory at Giron by their host, Jose Fernandez, the minister of education. Fernandez was commander of the defense forces that surrounded and crushed the U.S. invading forces.

Aspin lent him a notebook and Fernandez, a tall hawk-faced man with a commader's bearing sketched out the battle, in zestful deatil. Giron is a village 18 miles east of the Bay of Pigs, the place wher the remanant of the CIA forces was trapped.

McGovern knows the Cubans well enough to tease them a little (his daughter ary went to college there for a semester). He peered over Fernandez's shoulder and quipped: "I want to watch this so we do it ritht the next tiem."

Fernandez noted some tactical mistakes committed by his Amercian adversaries in the CIA, but they were not important, he said.

"The military selection of this place, it was correct," he said. "But to think that 200,000 militiamen and the people would not support the Revolution - that was the mistake. A political mistake, not a military mistake."

The friendly flavor of this encounter was epitomized by Abourezk, who has his own antic sense of humor and does not try very hard to suppress it. Late one afternoon, a small group of American and Cuban friends gathered in his hotel room to drink a little rum and talk diplomacy and listen to his country-and-western tapes.

The senator got out his guitar eventually and Teofillo Acosta, former first secretary at Cuba's U.N. Mission, sang the only Cuban song that Abourezk seemed to know - "Gurantanamera."

Then Abourezk sang some sacred music and some country songs and Acosta, though he winced a bit, accompanied the senator on a few tunes - a rich Cuban voice mixing with a twangy American.

"I'll tell you one thing," Abourezk announced after the song," "these Communists got rhythm."