Romney had Kid Rock and the Marshall Tucker Band in the wings for his late appearances in Ohio and New Hampshire.
"This is it," the challenger said in a last-minute emailed request for campaign donations.
"I will lead us out of this economic crisis by implementing pro-growth policies that will create 12 million new jobs. With your help, I will deliver real change and a real recovery. America will be strong again."
In his longest campaign day, Romney raced from Florida to a pair of speeches in Virginia to Ohio and then an election eve rally in New Hampshire.
Obama selected Wisconsin, Ohio and Iowa for his final campaign day, an itinerary that reflected his campaign's decision to try and erect a Midwestern firewall against Romney's challenge.
Vice President Joe Biden and Republican running mate Paul Ryan of Wisconsin went through their final campaign paces, as well.
In Sterling, Va., not far from Washington, the vice president accused Republicans of running away from their record, but added, "a leopard can't change his spots."
Ryan started out in Reno, Nev., where he said the president has come up short in his promises to change Washington and repair the economy.
"This may be the best that Barack Obama can offer, but this is not the best America can," he said, before flying off to Colorado and Ohio. Then it was home to Wisconsin, where he is on the ballot for re-election to Congress in case Republicans were unsuccessful in the presidential campaign.
Conscientious to the end, supporters kept knocking on doors in search of a possibly decisive vote.
In Enfield, N.H., Obama volunteer Sarah Ayres recalled driving up a deserted dirt road, unsure if she would find the house she was looking for. She turned down a long driveway, she said, got out of her car, and was met by a friendly, white goat.
"There were no people home, but the goat was there, so I don't know if I should count that as a contact," she joked.
Associated Press writers Beth Fouhy, Donna Cassata and Stephen Ohlemacher in Washington, Steve Peoples and Ann Sanner in Ohio, Philip Elliott in Colorado, Jim Kuhnhenn and Matthew Daly in Virginia and Holly Ramer in New Hampshire contributed to this story.