Neither rain nor heat stops Disney marathon runner Heather Montgomery .

Four characters in four days and 48.6 miles.

Heather Montgomery has put away the Minnie Mouse costume that she wore for the five-kilometer race Thursday, the first day of the Walt Disney World Marathon Weekend. She did the same with the Cheshire Cat getup from Alice in Wonderland that was her attire of choice for Friday's 10K.

Now it is on to Saturday morning's half-marathon, where if someone is spotted dressed up as Dopey, the dwarf from Snow White, that's probably Montgomery. And then the 28-year-old health-and-fitness blogger from Biloxi, Miss., will conclude her week of playing dress-up by donning a Ariel, the Little Mermaid, costume while running the marathon Sunday.

A Dopey idea to run four races in four days? They don't call it the Dopey Challenge for nothing.

"It is one of those things that you look at before you do it and say, 'Oh my goodness, I am going to do that?''' Montgomery said. "After it is over, you say, 'Oh my goodness, I just did that.'''

And she will not be the only one.

Of the estimated 50,000 runners who, Disney officials say, are taking part in the four races, 7,000 are attempting the Dopey Challenge. It is a concept that morphed out of the Goofy Challenge, a series that started in 2006 and includes only the half and full marathons.

Five thousand runners are competing in the Goofy Challenge this weekend.

"With us adding the 10K this year and including a Dopey Challenge option, this is going to be a one-of-a-kind event," said Darrell Fry, Disney's sports media director. "Where else can you do four races in four days and do just a hair under 50 miles?"

Who would want to? For some, such as St. Cloud's Amanda Tinney, the appeal is the atmosphere of running through the Disney theme parks, stopping to take pictures with Mickey Mouse and Donald Duck. Others, such as Todd Sontag of Oviedo and Michael Prince of Windermere, want to test their bodies.

"Doing this sounds crazy to me," said Sontag, a 38-year-old family physician. "In fact, my wife runs half marathons, and even she thinks I am crazy."

Said Tinney, who writes a blog about Disney: "A lot of people say a race is 90 percent mental. There will be times you don't think you can go on."

Lindsey Wolf, a 33-year-old physician assistant from Oviedo, said the Dopey Challenge has forced her to stay true to a commitment she made last year.

"I wanted to be in the best shape of my life by the end of 2013, and I am," Wolf said. "My parents don't understand why this is so important to me and why I want to tax my body like I will."

Competitors finishing all four races will receive six awards — medals for each race as well as ones for completing the Goofy and Dopey challenges.

"The majority of my friends are runners, but I don't know a whole lot of them who have ever attempted something like this," said Prince, a 34-year-old Windermere resident who is a producer for The Golf Channel.

Few have, but for those who will complete Sunday's 26.2-mile marquee event, crossing a finish line likely never will be more satisfying.

As for Monday?

"There is a reason I took Monday off," Sontag said. "I'll have pains and won't want to move."

jrwilliams@tribune.com or 352-742-5921