By Patricia Zengerle
ST. PETERSBURG, Florida (Reuters) - Newt Gingrich has come a long way. After his stunning victory in South Carolina, the Republican presidential hopeful who was tearing around Iowa two months ago in a rental car with a couple of aides has established himself in Florida with the apparatus worthy of a front-runner.
Gingrich has opened seven Florida offices with two more in the works, hired 14 paid staff and signed up 5,000 volunteers in Florida, 500 of them since his upset of front-runner Mitt Romney in South Carolina's primary on Saturday.
By contrast, Romney's campaign had just five staffers and three offices in Florida by early this week.
In a state that is often a graveyard for candidates who lack money, the former House of Representatives speaker just got an infusion of cash and leads Romney in opinion polls for Florida's January 31 primary.
Florida is the fourth and largest state to hold a contest in the 2012 Republican nominating process, which will choose a challenger to President Barack Obama in November's general election.
Clips in favor of Romney have dominated political ads so far in Florida, but Gingrich is about to challenge the former Massachusetts governor on the air waves as well.
A group that backs Gingrich spent $6 million on Tuesday on advertising, compared to $10.5 million spent by Romney backers in recent weeks in Florida.
The Gingrich spending, helped by a $5 million single donation, chips away at the dominance of Romney's campaign in Florida, which was long regarded as a well-funded machine that would cruise through the state and leave rivals in its wake.
The Gingrich surge resonates with some Republican activists in the state, including the small-government Tea Party members.
"I'm tired of everybody telling me who to vote for," said lawyer Deborah Schmidt, a Tea Party member from Tampa who attended a packed Gingrich rally at a St. Petersburg diner. She said she felt Gingrich best understood the pain that most Americans are feeling, something the "Republican establishment" might not understand.
Although the candidate is often late for events, Gingrich's campaign has come a long way in only two months.
Describing himself as the "non-traditional" candidate, he was stumping for the January 3 Iowa caucuses with a barebones shoestring operation run out of a rented car.
Now at campaign stops his red, white and blue bus is surrounded by a large entourage, including security guards, who rush him through the crowds.
"I should think the campaign on the ground is very good. I know some of the people he's brought in and they are very experienced," said Brian Crowley, editor of the Crowley Political Report blog on Florida politics.
The Gingrich campaign, once deeply in debt, raised more than $1 million in less than 24 hours after his victory over Romney in South Carolina.
Gingrich has jumped to the front in polls in Florida, but he can expect a tough fight to hold his lead over Romney, who blitzed Gingrich as a disgraced politician and Washington influence peddler in a debate in Tampa.
FLORIDA UP FOR GRABS
Any successful candidate in Florida has to be able to communicate with widely divergent audiences, from Miami, a largely Hispanic city, to communities in the northern panhandle that would fit into the country's southern Bible Belt.
"In Florida, coalition-building is the key. There's not one particular segment of the Republican electorate that is going to guarantee any candidate a victory," said Carlos Curbelo, a Miami-based Republican strategist.
"I think Florida is up for grabs," he said.
With 19 million residents and more than 11 million registered voters, Florida is more than twice as big as the three previous early-voting states - Iowa, New Hampshire and South Carolina - combined.
Unlike in the other states, door-to-door campaigning is not the way it's done in Florida, where TV advertising is king.
"It's a wholesale state. The others, especially Iowa and New Hampshire, are retail states," said Peter Brown, who directs polling in Florida for Quinnipiac University.
Former Arkansas Governor Mike Huckabee, who came in fourth in the 2008 Republican primary, is routinely cited as an example of what happens to candidates who can't ante up enough to get in the game in Florida.
"Governor Huckabee won Iowa and his star was rising. And he got to Florida and nothing good happened and they asked his campaign manager what happened and he said, 'We got to Florida and we needed $4 million and we didn't have it. It's not much more complicated than that,'" said Palm Beach County Republican Party Chairman Sid Dinerstein.
(Additional Reporting by Jane Sutton in Miami and Alina Selyuk in Washington; Editing by Alistair Bell and Doina Chiacu)