It was an all-American pilgrimage, a thoroughly midwestern affair, a cross between a Sunday church picnic and a state fair. In buses, campers, vans and station wagons they came, many arriving before the first orange fingers of dawn crept over the cornfields of Living History Farms.

Hiking miles through the chill morning air, lugging chairs and blankets, they gathered around a modernistic altar in this pasture of Iowa, a half-million strong, waiting several hours before they saw and heard Pope John Paul II, the Polish foundry worker's son who in four days in America has become a media superstar.

"Here in the heartland of America, the valleys and the hills have been blanketed with grain, the herds and the flocks have been multiplied many times over," said the pope, standing erect on a wind-blown hillside. "By hard work you have become masters of the earth and you have subdued it."

Peering down at his audience of farmers and townsfolk from every state in middle America, their multicolored caps, parkas, jackets, banners and pennants blowing in the breeze like waving wheat, the pope said that with the bounty of their lands came a special responsibility.

"God destined the earth and all it contains for all men and all peoples so that all created things would be shared fairly by all mankind under the guidance of justice tempered by char-ity," he said. "You who are farmers today are stewards of a gift from God which was intended for the good of all humanity. You have the potential to provide food for the millions who have nothing to eat and thus help to rid the world of famine."

The people here did not demonstrate the wild enthusiasm of the crowds John Paul won over in New York, Boston and Philadelphia. The waited quietly for him to speak and applauded politely when he was done. For this, there were many reasons.

Many in the crowd were simply too tired from their long pilgrimages to jump and yell and scream. There was also the sense here in Grant Wood country, as one called, it, that one does not shout, does not applaud, does not scream when the Vicar of Christ speaks.

"I just think we're so awed that it's happening," said Francis Thorne, a Leavenworth, Kan., real estate agent who drove all night with his wife and five children to see the pope. "I just think it's not like a New York crowd where you see a celebrity every day."

And then there was the fact that Iowa and its neighboring states -- unlike the large cities on the pope's tour -- are not strongholds of Catholicism. Here, most religious people are Lutherans, Methodists, Baptists. John Paul was harshly reminded of this as soon as he arrived. His motorcade drove past the airport Baptist church where the marquee that usually announces prayer services admonished the faithful to "call no man father."

Before the mass at Living History Farms, the pope traveled to St. Patrick's Church near the town of Cumming for a quiet, lyrical celebration with the church's 205 parishioners. "On your farms, you are close to God's nature," he said, his audience listening in complete silence. "In your work on the land you follow the rhythm of the seasons, and in your heart you feel close to each other as children of a common father and as brothers and sisters in Christ."

The pope sat on a red velvet chair in front of the altar of the 111-year-old wooden chapel. Nearby was the church's pastor, the Rev. John Richter. The autumn sun filtered through 10 stained glass windows. Seated in the 14 rows of wooden pews before him were the parishioners, many of them descended from the Irish immigrants who founded the parish in 1852 after fleeing the potato famine of their native land.

They heard the pope praise "the simplicity of your life style and your closeness to the fertile ground."

Then, under the shade of 10 maple trees, the pope attended a lemonade and ice cream picnic with the parishioners -- a gentle contrast to the loud and hectic events that had dominated his tour through the cities of the Northeast. "This was the only place where the church was filled with lay people, not priests, nuns and seminarians," said one parishioner. "The pope was near the people."

But the visit to Iowa also posed several stiff challenges to the pope, both directly and indirectly, of a church in transition. The mass at Living History Farms, for example, was preceded by an ecumenical service, featuring Protestant and Jewish religious leaders.

And among those originally invited to take communion from the pope was Gustave Rhodes, a black Louisiana sugar plantation worker who happens to be a Baptist. Rhodes was told he would not be allowed to take communion when he arrived Wednesday night. "I'd love to take communion on behalf of all the other sugar cane workers," he said. "I don't see being a Baptist makes any difference."

The more important social issue that confronted the pope here, however, was land ownership. Bishop Maurice Dingman of the Des Moines diocese heads the National Catholic Rural Life Conference and is an outspoken critic of large corporate farms. He has repeatedly said they are destroying the fabric of rural life and believes the church and government should take steps to preserve family farms.

Dingman, one of the nation's more liberal bishops, had said he hoped the pope would tackle that issue while in Iowa. John Paul did not quite do that, although he did speak out firmly of the need for land conservation, rural development and the virtues of farm living.

On this day in Iowa, however, there was a sense among many of the people that the pilgrimage was an event equal to the words and presence of the pope. Bill Wagner, architect of the chapel built for the mass at Living History Farms, looked out over the scene and said, "I think it's wonderful, just fantastic." Asked if he meant the spectacle of the pope and the altar, he responded, simply, "No, I mean us."

These Midwest pilgrims came prepared today as they would for a tailgate party before a professional football game in Minneapolis or Green Bay. They brought vacuum jugs, camp stools, binoculars, tape recorders, radios, paperback novels, playing cards and portable televisions.

"We've got everything but scotch here," said Dick Kibbie, a particularly well-equipped visitor as he fiddled with the dial on his portable TV. "And we'd have scotch, too, if we'd known it was going to be this cold."

Almost 6 percent of the population of Ashland, Neb., a village of about 2,000, was camped 150 yards from the huge brown altar that had been built for the pope from wood taken from an old corn crib.

"We've been planning for this trip -- we call it a spiritual pilgrimage -- from the moment it was announced the pope was coming to Des Moines," said Rev. Zygmund Rydz, who grew up in Poland. "We had a food chairman, we had a transportation chairman, we had a weather chairman. He prayed for good weather, and boy did he do his job."

Des Moines, a city of 194,000 with a small town flavor, has been preparing for the pope's visit for weeks. Fearful that crowds of more than 500,000 would overrun the city, planners overreacted, closing streets in whole suburbs to traffic 24 hours before the people were scheduled to arrive.

In the end, they scared people half silly, and by Wednesday it was apparent that the crowd would be far smaller than anticipated. Hotel rooms, impossible to reserve for a month, suddenly became open. Restaurants were half empty.

The pope began his day in Philadlephia with visits to churches in two ethnic neighborhoods and climaxed his 20-hour visit to that city with a huge worship service in the Civic Center. It was there that he made his first mention of the growing movement in the United States to admit women to the priesthood, taking a strong stand against it. The pontiff also used that occasion to stress the importance of celibacy for priests.

But later, speaking at the Ukrainian Cathedral of the Immaculate Conception, a branch of the church that allows priests to marry, John Paul did not challenge their practice. Catholic unity, he said, means "strengthening and preserving intact the communion of the universal church, while safeguarding the existence of the legitimate individual traditions within it."

The pontiff left Philadlephia shortly after noon. At the airport, thousands of Catholic schoolchildren sang and held a banner which said in Polish: "Thank you Father for coming to Philadelphia." As the pope approached his waiting airplane, he walked over to shake the hands of a line of city policemen, greeting each one as the heleted officers bowed to kiss his ring.