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ABC's Shushannah Walshe and Michael Falcone report:

DES MOINES - He's only set foot in Iowa a handful of times during the primary season, and by all accounts, he's only spending a fraction of the $10 million he invested in the state four years ago, but Mitt Romney has something else going for him.

On the eve of his sixth trip to the state this year, the former Massachusetts governor is counting on a network of highly-motivated, politically-connected volunteers willing to engage in door-to-door combat for him even as Romney spends more time in other early nominating states.

Mary Kramer is one of them. She's a former ambassador to Barbados and the Eastern Caribbean, she served for seven years as president of the Iowa state senate, and she's an author who gives speeches around the state.

Though she said she doesn't use her speaking engagements as a platform to tout Romney specifically, she's not shy about telling her audiences who she is backing.

"It is a nice way to open that door," Kramer said in an interview with ABC News, adding that as she travels Iowa she's been "quietly" trying to stir up more support for Romney.

Whenever Kramer, who lives in a Des Moines suburb, does face-to-face advocacy on Romney's behalf she also looks for opportunities to bring new volunteers into the fold.

"Even if they talk to people in church, talk to people at Rotary, talk to people at Kiwanis, talk to people at the health club," she said, "it's important to have those conversations."

With only five full time staffers in the state, the Romney campaign is relying on Kramer and a cadre of invested "super volunteers," who are not only willing to engage in an old-fashioned game of persuasion with friends and neighbors, but whose prominence as elected officials or business professionals allow them to use their talents and influence to help with the campaign's efforts here - free of charge.

Many of these volunteers hold positions in Romney's Iowa campaign organization that might have been filled by paid staff four years ago when Romney invested much more heavily in the state. Back then Romney had a whopping 52 paid employees in Iowa alone.

Native Iowan Kent Lucken is currently wearing two hats in the Romney campaign - foreign policy adviser and northwest Iowa organizer. Lucken, who grew up on a farm outside Sioux City is taking time away from his job as an investment banker in Boston to assist the campaign between now and Jan. 3.

"What was in the hands of 10 regional coordinators before, is now divided up among four to five people, some of us being volunteers," Lucken said. "This time it's considerably different."

Lucken, who has temporarily moved back to his family's home in Iowa, has been combing through lists of supporters from the previous election cycle, indentifying who is sticking by Romney this year and who could serve as potential caucus leaders.

Mark Hudson, a lawyer from Marion, Iowa makes phone calls to voters and helps out with precinct organizing. He's also a volunteer legal counsel for the campaign. Hudson, who was not a Romney supporter in 2008, referred to Romney's effort here as "much more volunteer-based and much more grassroots."

He said this year's campaign structure is "more fiscally responsible" than four years ago.

"They learned a lot in the campaign last time. This time it's smaller and they are being smarter with volunteers," Hudson said. "We are talking to people, getting out in the community, making phone calls, making sure we get the people who support us out to the caucuses on January 3."

Chad Airhart, the elected recorder of Dallas County, Iowa, serves on Romney's statewide leadership team and said in an interview that he's "actively working to spread his message and recruit other supporters."

Airhart is active in the Iowa Republican Party's central committee and his local chamber of commerce, among other groups. He routinely talks to other members about why he's supporting Romney.

"Nobody's more qualified to be your party's nominee and our next president," he said. "It's been easy to say that Mitt Romney's my guy."

Sources close to the campaign say there are no plans to surge in dozens more paid staff members in the days leading up to the Jan. 3 caucuses. Rather, they will continue to make the most of their volunteer corps as they focus on the some of the biggest Iowa counties that account for the majority of caucus-goers.

Chris McLinden first hosted Romney and his wife, Ann, at his home in October 2007 and since then he's remained close to the Romney team. But McLinden, a headhunter who owns his own business, acknowledged that supporters "would like to see more of him, they would like to see more intensity."

"At this point last time whether it is the Romney campaign or the Huckabee campaign…precinct campaigns were chosen for a lot of the candidates," McLinden said. "At this time last time … a lot of them had their blueprint and had their precinct captains, caucus captains."

McLinden added: "Nobody has called me to be a precinct captain and I would be probably the logical one to call. It's been more of a pull than a push. I mean you almost have to get information from the campaign vs. them calling me everyday."

Still, he plans to caucus for Romney in Van Meter, Iowa. His message about the candidate will be simple: "He's the real deal."

David Oman, a former chief of staff to Iowa Gov. Branstad, has been a long-time Republican Party leader in the state. Oman ran for governor a dozen years ago, and like many of Romney's volunteers, he lives and breathes Iowa politics

Oman said he spends about an hour-and-a-half each day working with Romney's finance team and while he backed Mike Huckabee in 2008, he said that in 2011 Romney is "running a smarter campaign" and the group of volunteers is "growing."

"I'm not on the staff, I'm not paid," Oman told ABC News. "There are a lot of people in the same boat and it's fun to see the breadth of interest in the governor. We are hoping that will grow in the weeks ahead and serve him on caucus night."