At a farmers' market in Marin County, north of San Francisco, stall-holders and shoppers looked on approvingly as Camilla heartily sampled much of the produce.
"She's really down-to-earth," said Wendy Earl, 58.
At some stops, placards praised the prince's organic credentials and entreated him to speak out against the war in Iraq.
In a speech Monday to about 300 business, government and academic delegates, Charles appealed for action in the face of the "almost complete global scientific consensus" on climate change.
Environmentalists say the U.S. government has been slow to recognize the threat of global warming, and the prince urged the United States to "use its power and influence to help create a sense of unity in common cause" on the issue.
Also on Monday, the last full day of the trip, the couple visited the "edible garden" at Martin Luther King Jr. Middle School in Berkeley, a kitchen garden converted from waste ground where students grow and prepare their own food.
Charles and Camilla were met by Maria Shriver, wife of California Gov. Arnold Schwarzenegger, and the Berkeley chef Alice Waters as they met pupils preparing food in the school kitchen.
The couple joined pupils in offering thanks before sampling a harvest soup made of vegetables from the school garden.
"I'm thankful for all nature's gifts," Charles said.
"I'm going to be very thankful when I've eaten this soup," Camilla added.
The British media have long held that many Americans remain in thrall of the glamor of Princess Diana and the fairy-tale romance of her marriage to the prince. Camilla is the villain of that story _ the woman Diana meant when she said "there were three of us in that marriage."
But only a handful of Diana die-hards dogged the tour, vastly outnumbered by Camilla well-wishers.
Many Americans _ especially women _ seemed won over by the middle-aged royals' long-burning love.
"I think it's a fairy-tale that they got together finally," said P'Nina Campbell, a cashier waiting to catch a glimpse of the couple outside the National Institutes of Health near Washington.
In Point Reyes Station, Calif., Cari Lee, 45, waited outside a farmers' market holding a sign reading, "We love Their Royal Highnesses Charles and Camilla."
"I'm a newlywed as well, so I understand their bliss," she said.
