Hundreds of people ran the streets of central Temecula on Sunday: some trying to earn a cash prize, others looking to support local causes, and the rest working to stay healthy and have fun.

The inaugural "Run for the Hills" 5K run/walk fundraiser drew hundreds of participants to Ronald Reagan Sports Park, where families, retirees and avid runners came together to raise money for three local causes, including to preserve open spaces and aid low-income families.

The event was held by Save Our Southwest Hills, a 10-year-old nonprofit dedicated to preserving the hills flanking the west side of Southwest County, from Murrieta to Rainbow.

For the last five years, its main focus has been to fight the development of a quarry southwest of Temecula.

While that effort has included street protests, large groups of people spelling out "no quarry," and other high-profile campaigns against the company that wants to build it, Granite Construction, the fundraiser Sunday represents an emerging effort to sometimes take a different approach to the situation, organizers said.

"We all know who the big, bad people are," said the fundraiser's organizer, Mariann Byers. "That doesn't need to be repeated all the time. We are going positive."

In addition to the race, Byers cited the nonprofit's recent funding of a major cleanup of Ronald Reagan Sports Park by a group of about 125 local Boy and Girl Scouts, and its part in an effort to give movie director James Cameron an award for his environmentally friendly film "Avatar," as other examples of positive efforts.

What's more, the inaugural race is one of many to come, she said.

In future years, the nonprofit hopes to use the proceeds to partner with the city of Temecula and buy swaths of undeveloped land for conservation, Byers said.

As for this year, the benefactors include Save Our Southwest Hills; the Santa Margarita Ecological Reserve, owned by San Diego State University Foundation; and the Temecula-Murrieta Rescue Mission.

Although the rescue mission is more about feeding low-income families than preserving the environment, organizers said it was worthy of help.

"It always helps when you are giving to something that's deserving," said Jerri Arganda, a member of the Southwest Hills group. "The rescue mission is a popular, well-known group that needed support."

Byers estimated that the fundraiser took in about $20,000, but that figure does not include the cost to put it on.

Nevertheless, it was a good outcome, thanks in large part to nine major sponsors and 25 small businesses that supported the event, she said.

"The support from the community has been overwhelming," she said. "This is a chance to really make people aware of our beautiful hills."

About 320 participants signed up for the race, but when factoring in children and others, about 500 people raced Sunday, and dozens of others volunteered to help, Byers said.

Among the volunteers was Rainbow resident Robin Dixon, 54, who stood along the course in a bright-orange vest and managed foot traffic while cheering people on.

She was situated toward the end of the course, which wound along Pauba, Ynez, Margarita and Rancho Vista roads.

"Thanks for coming out and supporting us today," she called out to groups of people walking by her station. "You're almost there."

Dixon said she was happy to spend a few hours Sunday morning helping the cause.

She lives a few miles from where the quarry would be built and said she doesn't want to hear the blasting two to four times a day.

"I'm excited," she said. "There is a lot of people joining us today."

Racers came from as far away as Texas and Florida, organizers said.

Among the crowd was Las Vegas resident Karen Cerezo, 36, a runner who said she just happened to be in town and decided to participate.

"It was well organized," she said after finishing the race in about 30 minutes.

"And there were a lot of kids, too ---- which is cool," she said. "We don't get a lot of kids at events like this in Vegas."

Pediatrician Dan Robbins, spokesman for the group Physicians Against the Quarry, said he brought his wife and children to the event because it's healthy and fun, not necessarily to represent doctors.

"It's actually a beautiful thing to hold an athletic-based event," he said. "As a physician, we promote good health and clean air. This brings both of those things together. Improving the environment improves the community's health."