No more excuses about it being too early or claims that voters aren't yet paying attention. Want to be president? Get moving now.

On the trail in Iowa and New Hampshire, candidates are engaging in the type of retail politics that those states are known for.

Ted Cruz is on the bus, seemingly trying to greet every voter in Iowa over the course of a week. Chris Christie walked into a Rotary Club luncheon. And Hillary Clinton's press corps is now riding in style.

Here are scenes from the trail from our far-flung correspondents.

Waiting for Trump

Sara Murray in Lowell, Massachusetts

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As the sun went down and the temperature dipped into the teens, Massachusetts voters scoffed at the notion that their early-state brethren wouldn't show up to vote for Donald Trump come Election Day.

"You see the line down here and you know how cold it is?" said Sharon Dupont, 63, as the line behind her continued to grow. "They'll come out. They'll vote for him." (Dupont admitted that she's still torn between Trump and Cruz.)

Political pundits and rival campaigns have questioned whether Trump's supporters -- a mishmash group of reliable Republican primary voters, first-time primary participants and discouraged Democrats -- will turn out in early nominating contests, particularly in bad weather or more daunting settings like the Iowa caucuses.

Dracut resident Mark Feeney, 63, said he wasn't concerned. "They're saying that because they know people are going to come out and vote for Donald Trump," he said.

Feeney and his wife lined up at 10 a.m. Monday to catch Trump's rally in nearby Lowell. They waited roughly seven hours for the doors to open. The event wasn't schedule to start until even later, 7 p.m.

"They don't want to believe it," Feeney said. "He will be our president."

With the Iowa caucuses less than a month away, the GOP frontrunner isn't hunkering down in the traditional early voting states. Asked why the campaign was in Massachusetts today, campaign manager Corey Lewandowski exclaimed, "It's a Super Tuesday state!" And today, Trump had Massachusetts -- whose 42 delegates are up for grab on March 1 -- all to himself.

Bill Clinton's 2016 debut

Brianna Keilar in Nashua, New Hampshire

Bill Clinton is on the campaign trail for his wife for the first time this cycle and it's clear he is on his best behavior.

He is playing the role of presidential spouse, introducing voters to a side of his wife they might not know much about: the early years when he first met her (45 years ago, he reminded New Hampshirites today. That's older than Marco Rubio! Maybe a fact that highlights both candidates' vulnerabilities?) and soon after when she was a "lady lawyer" as one "crusty" old judge in Arkansas referred to her pejoratively. But aside from talking about Hillary Clinton's achievements as a woman he hasn't focused on women as Donald Trump hammers him for his past infidelities.

Voters here, it seems, don't want to hear about it. Jennifer Gerber, an undecided Democrat at his second event in Exeter, told my producer Pallavi Reddy, "Trump is one to talk. Trump shouldn't throw stones, he has a lot of skeletons in his closet that are fair game as well. He has terrible relationship issues, problems with his family, problems with bankruptcy, you know? He's got issues too."

Some besties meet for coffee. @kwelkernbc and I live shot. pic.twitter.com/taqj0zEYsn — Brianna Keilar (@brikeilarcnn) January 4, 2016

Asked by a reporter about whether his indiscretions during the 90s are fair game, Clinton dodged, saying Republicans will have to decide and he is here to tell voters his wife would make the best president.

Normally he is game to really engage with reporters, but he's focused much more on voters on the rope line on this swing, aware he can't totally avoid questions from the media but quick to dispense with them without saying much. The man who freelanced in 2008, fiercely defending but ultimately hurting his wife's efforts, is buttoned up and walking the line.

For now, anyway.

Hillary Clinton's press corps rides in style (kind of)

Dan Merica, somewhere on Interstate 80 in Iowa

The first ever Clinton press corps bus trip is a somber and quiet affair so far. pic.twitter.com/uceWsr7dqv — Dan Merica (@danmericaCNN) January 4, 2016

Hillary Clinton's campaign reached a new milestone on Monday: inaugurating their first campaign bus of the presidential cycle.

After the Democratic frontrunner's first event of the day in Davenport, Iowa, about a dozen reporters sauntered onto a large bus headed for Des Moines and Clinton's third and final event of the day. Drawn in by promises of power, wireless internet and cold-cut sandwiches (who said reporters are needy?), the reporters forgoed the classic long drives of Iowa to be driven down I-80 by a professional bus driver hired by the campaign but paid for by the news organizations.

The coach was more Greyhound than moving party, however. Reporters spent most of the time with their heads down and headphones on, jamming on stories, interviewing sources and going through their notes.

"Not exactly a party bus," remarked Amy Chozick of The New York Times.

The Clinton campaign put on advance staffer on the bus and a Secret Service agent also joined the ride. Neither livened up the mood.

The bus is a new reality for a campaign that is trying to crisscross the state with weeks until Iowans decide who they will support for president. With so much driving time in Iowa - the state is 310 miles from the Missouri River in the west to the Mississippi in the east - it helps people keep up with a candidate who can do more events because she can fly. Reporters can work while moving - keeping up with the reality of the 24 news cycle. What's more, with Bill Clinton now on the trail, the beat just doubled in size.

Hillary Clinton remembers 2008

Jeff Zeleny in Cedar Rapids, Iowa

A big afternoon crowd for @HillaryClinton in Cedar Rapids. "You are the first line of defense against Republicans." pic.twitter.com/CuXmYBKe8E — Jeff Zeleny (@jeffzeleny) January 4, 2016

Hillary Clinton made clear Monday that a painful lesson from her 2008 campaign remains seared in her memory: Few things can humble a confident front-runner more than losing the Iowa caucuses.

It was eight years ago when a third-place finish in Iowa exposed severe shortcomings in Clinton's presidential campaign and ultimately paved Barack Obama's way to the White House.

This time around, her campaign insists it is taking nothing for granted.

"I know that if I get off to a good start here in Iowa, we are halfway home," Clinton told Iowa voters at the first stop of a two-day visit.

But only halfway.

She did not directly mention Bernie Sanders, her top Democratic rival, but her team here is far more fixated on him than her speeches might suggest. Sanders has built an enthusiastic core of supporters who would like nothing more than to give Clinton another lesson in Iowa.

Clinton spoke to enthusiastic crowds, who came by the hundreds, not the thousands, to Davenport and Cedar Rapids. Her audiences were filled with far more hard-core, committed supporters than undecided voters.

She focused her attention relentlessly on Republicans, bluntly declaring that she is the only person who can stop the GOP from winning back the White House.

"You are the first line of defense against Republicans," Clinton said, urging Iowans to take seriously their duty of voting.

Riding the bus with Ted Cruz

Sunlen Sefarty in Winterset, Iowa

Ted Cruz hasn't set foot in Iowa for exactly 30 days, and he's neck-and-neck with Donald Trump for the lead here.

Starting Monday, Cruz will attempt to show up in the most classic of Iowa ways: at Pizza Ranches, firehouses, general stores, Christian bookstores, firehouses and schoolhouses.

The Cruz campaign, out with splashy new bus signage today emblazoned with "Courageous Cruzer" and "Cruzin to Caucus" is trying to make Iowa caucus-goers feel -- and visibly see -- that they are a priority, in a state where voters have famous high standards for needing to get to know their candidates.

The plan is for Cruz to log over 1,038 miles, making 28 scheduled stops in far-flung parts of the state over the next six days.

At his first stop in Boone on Monday-- the start of what will be nearly a 13-hour-day, with six stops, the last starting at 10:45 pm CT time, Cruz wasted no time framing his message, projecting himself as the one to beat in this state.

"Just about every candidate in the Republican field is attacking me, I guess something has changed," Cruz said at a Christian bookstore in Boone this morning.

.@tedcruz lays out his first day in office at Guthrie Center's Prime Time Restaurant, his third Iowa bus tour stop pic.twitter.com/KqbcdboQnv — Betsy Klein (@betsy_klein) January 4, 2016

Marco Rubio's early morning

Marco Rubio speaks at a pancake breakfast at the Franklin VFW on December 23, 2015, in Franklin, New Hampshire.

Athena Jones in Hooksett, New Hampshire

Several dozen people filled a small section of the American Legion Hall here where Florida Sen. Marco Rubio delivered his pitch for why he would be the strongest candidate on national security.

The event space was only about half full at the scheduled 7:30 a.m. start time, and Rubio supporters offered donuts and coffee to people as they waited for Rubio to arrive. By the time the event got under way, about 45 minutes after the scheduled start time, all of the chairs in the room were occupied and a few people were standing.

And while it wasn't a particularly electrifying or arousing speech and Rubio did not spell out specific policy proposals, he got a good reception from the crowd, which warmed up even more when the Q-and-A began.

Rubio cracked jokes during the Q-and-A, prompting laughter, but he also talked about serious issues like a teammate of his son's who was killed recently by a stray bullet. When a voter asked him what she should say to her friends who are worried about Rubio's stance on immigration, he argued that no other candidate knows more about the issue than he does, in part because so many in his family and his community are immigrants.

Rubio goes to Iowa -- and after Ted Cruz

Manu Raju in Burlington, Iowa

As he strode before a packed audience here at a local library, Rubio had Cruz on his mind.

"Talk is cheap to say you're going to carpet bomb ISIS," Rubio said, donning a blue fleece with his name emblazoned on it. "How are you going to do that if you don't have the intelligence to do that?"

It was the latest shot at Cruz in an escalating war of words between the two camps -- as the two men increasingly see each other as a major threat to the GOP nomination. Rubio has increasingly seized on Cruz's support for an intelligence bill that overhauled the National Security Agency's bulk data collection program -- and for backing budget proposals calling for a reduction in defense spending.

Rubio's confidantes believe that there are many undecided Iowa voters and can still pull off an improbable victory here next month -- or at least finish in the top three, giving him some fresh momentum headed into New Hampshire. But to get there, Rubio believes he needs to cut significantly into Cruz's support in Iowa, a state dominated by social conservatives.

Indeed, here at the town hall event Rubio wasn't afraid to showcase his Roman Catholic faith when a man asked if he would listen to God's advice as president. Rubio's response: "As a Christian, I believe that Jesus is God."

While he repeatedly attacked President Barack Obama during his appearance here, he rebutted a voter who called him "a Marxist," saying, "I wouldn't go that far." And he also gently rebuked Donald Trump, as a voter praised the brash businessman's penchant for bullying politicians.

"Being angry by itself is not enough," Rubio said.

About to go live on CNN from Burlington, Iowa here at a Marco Rubio townhall A photo posted by Manu Raju (@manu_raju) on Jan 4, 2016 at 11:36am PST

Chris Christie makes the rounds at the Rotary Club

Phil Mattingly in Manchester, New Hampshire

"Showtime is over."

With the turn of the calendar, that's the message Chris Christie repeated throughout his New Hampshire campaign stops on Monday. The not-so-subtle dig at Republican front-runner Donald Trump showed up in what Christie's aides promoted as an important speech on "American leadership" in the morning. They emerged again in his first town hall of the day an hour later in Manchester.

It's a message Christie, whose campaign strategy is reliant on a big showing in the February 9 primary here, needs to sink in if he's to chip away at Trump's double-digit polling lead in the state. It's a lead he's taken bits and pieces out of in recent weeks, moving himself firmly into the top tier of non-Trump candidates in the state. And it's on the back of the town-halls -- he held more than 40 in the state in 2015 -- where he's made his move.

While reports on Christie as the brash, in-your-face New Jersey pol have at times reached caricature-esque levels during his time as governor, his town-hall style is more nuanced and tailored. He walked unannounced into a Manchester restaurant filled with Rotary Club members for his event today. It wasn't a packed arena, and his arrival wasn't punctuated by rock music. As Christie walked up to the first of the 15 tables in the restaurant, he startled one woman.

"Oh my. There you are," she said, putting her fork full of grilled haddock back onto her plate as she stared up at the New Jersey governor suddenly standing over her. Christie introduced himself. So did his wife, Mary Pat. ("Hi, I'm Mary Pat. I'm the wife. I'm the other half," she said, even as it was clear everyone knew who she was.)

It went like that across all of the 15 tables in the room, Christie shaking every hand and making small talk. As is always the case with Christie events, audience questions took priority over a lengthy speech.

They spanned from President Obama's looming executive action on guns, to campaign finance, to entitlement reform, to the military spending to GDP ratio of NATO allies. Christie took each with his usual mix of serious policy discussion, some humor, a bit of bluster, plenty of flattery and at times a combination of all four.

"Watch it, Father," Christie, to laughs, said at one point to a priest who pressed him on whether he'd promise to come back to the Manchester Rotary Club in New Hampshire as president. "I obviously made an awful choice calling on the Father. You put me on the spot."

I asked Christie after the event how he defined success in the state and he demurred, saying it was too early to really weigh in given the state's primary voters tend to decide on candidates late. But to voters a few minutes earlier, he made very clear the stakes at play.

"You will take this race from 12 candidates down to four on February 10," Christie said. "You will do that."