Tears were flowing and emotions ran high as mourners paid their final respects Thursday to Sen. Edward Kennedy, known affectionately as Teddy, the youngest son of a political dynasty that spanned the 20th century.

The doors have opened for the public viewing of Kennedy outside the John F. Kennedy Presidential Library and Museum where mourners had collected for hours before the viewing Thursday.

The casket arrived after a motorcade traveled 70 miles from the family compound in Cape Cod past sites of significance to his life.

Hundreds of people lined the route to the library, where his body will lie in repose for two days.

He is to be buried Saturday at Arlington National Cemetery in Virginia.

Thousands of spectators gathered in Hyannis Port and Boston, clutching cameras, tissues and at least one flag of Ireland, the Kennedys' ancestral homeland. Motorists stopped their cars on overpasses, hoping to catch a glimpse. Crowds applauded and cheered for the late senator as the motorcade made its way through Boston. News helicopters whirred overhead.

Virginia Cain, 54, said she walked just under 2 miles from her summer home in Centerville to the roads leading to the Kennedy compound so she could witness history.

"I can remember where I was when President Kennedy died, and I'll remember where I was when the senator left Hyannis Port," she said.

The late senator's loved ones -- including niece Caroline, daughter of former President John F. Kennedy, and son Patrick, a Rhode Island congressman -- arrived before noon for a private Mass at the family compound in Hyannis Port.

Relatives watched afterward from near the house as the flag-draped casket was loaded into a hearse, then took turns touching the vehicle on the way to their cars. As the motorcade pulled away for the 70-mile trip to the John F. Kennedy Presidential Library and Museum, Patrick Kennedy sat in the passenger seat of the hearse, near tears.

The motorcade was to pass several sites important to the senator on the way to the library, which he helped develop and where he will lie in repose until Friday, a Senate office statement said. By 3 p.m., when the library closed its exhibits, more than 100 people were waiting for the doors to reopen in the evening for a public viewing.

Ellen Freed, 58, of Brookline, arrived about 2:30 p.m. Freed, who is disabled because of epilepsy, credits Kennedy for her federally assisted housing.

"I live in a HUD building, and if it wasn't for Ted Kennedy, I would be homeless," she said.

James Jenner, a 28-year-old culinary student from Boston, placed the Red Sox cap he was wearing outside, where other mourners had left flowers, small American flags and a stuffed teddy bear with angel wings.

"It was Teddy's home team," Jenner said. "It just seemed appropriate to leave him the cap. It symbolizes everything that he loved about his home state and everything he was outside the Senate."

Trudy Murray, 86, a native of Ireland who later lived in England, said Kennedy helped her and her family get visas when they moved to the United States in 1969.

"I loved Ted Kennedy. I cried yesterday when I put on the TV and saw that he had passed away," said Murray, a retired nurse who now lives in Brockton.

"He made his mistakes, but I don't even want to hear them. I forgive all of them because he was such a good man," she said.

A private memorial service is planned at the library Friday evening and a funeral Mass on Saturday morning at Our Lady of Perpetual Help Basilica -- commonly known as the Mission Church -- in Boston. President Barack Obama is scheduled to speak at the funeral.

All the living former presidents will also attend the funeral, said a person familiar with the arrangements who spoke on condition of anonymity because he was not authorized to release details.

Shortly before the Mass, 44 sitting senators and 10 former senators will be among a group of about 100 dignitaries paying their respects at the library before heading to the cavernous basilica.

Among them will be former U.S. Sen. Birch Bayh, of Indiana, who pulled Kennedy from the wreckage of a small plane that crashed near Springfield, Mass., in June 1964. The pilot and a legislative aide were killed, and Kennedy suffered a broken back.

Kennedy's favorite song, "The Impossible Dream" from the musical "Man of La Mancha," will be played at one of the services, according to the person familiar with the arrangements.

Thursday's motorcade was expected to go by St. Stephen's Church, where his mother, Rose, was baptized and her funeral Mass celebrated; cross the Rose Fitzgerald Kennedy Greenway, the Boston park that he helped create and that is named after his mother; and pass historic Faneuil Hall, where Boston Mayor Thomas Menino was to ring the bell 47 times, once for each year Kennedy served in the Senate.

Kennedy will be buried Saturday evening near his slain brothers -- former President Kennedy and former Sen. Robert F. Kennedy -- at Arlington National Cemetery in northern Virginia.

The Associated Press contributed to this report.