At any given time, Vivian Dixon is preoccupied with the minutiae of maintaining luxury homes around the country. One minute she's tracking down a handyman to fix cracked marble in the master shower of an 8,000-square-foot mansion in California; the next she is worried about the toads invading a koi pond on the grounds of a $12 million estate in Hawaii.

"It's exhausting," she says. "A full-time job."

Ms. Dixon, 62, is an estate manager--for herself. She and her husband John Chapple, 66, who founded Seattle-based Nextel Partners in 1998 and sold the telecommunications company to Sprint Nextel for close to $9 billion in 2006, split their time between four parts of the country.

In the winter, they spend a month or two at their Balinese-inspired contemporary on the Big Island of Hawaii, and in the summer they spend a month in a renovated lake home on Madeline Island, Wis. The rest of the year they shuttle back and forth between their primary home in the northern Seattle suburb of Woodinville, Wash. and their mansion in the Los Angeles suburb of Rancho Palos Verdes, Calif. They are renovating a fifth property in Redmond, Wash., outside Seattle, while also maintaining a condo at the Four Seasons Hualalai resort, which is near their other Hawaii home.

To handle such a portfolio, Ms. Dixon takes a systematic approach, hauling around three bags of house stuff from place to place. There is the "To Do" bag, the "Done" bag and the "Follow Up" bag. In between walking her mixed terrier Spence and baking, much of her time at each house is spent unpacking boxes or decorating and redecorating rooms.

Every state has its own critters to combat: termites in California, swarming flies in Wisconsin, wolf spiders and stink bugs in Washington and goats and mice in Hawaii. Those toads in the koi pond? Ms. Dixon used a BB gun to get rid of them.

Yet California is where Ms. Dixon sees her family; Mr. Chapple has an emotional attachment to Wisconsin; Seattle is their main residence and Hawaii is just beautiful.

Mr. Chapple says he doesn't mind moving around, as long as he has friends to have lunch with and somewhere to retreat to watch sports on TV. "We don't go on vacation. We just go to our homes," he says. To keep him happy, Ms. Dixon decorated areas of the homes in Hawaii, Washington and California bright orange and blue in honor of Syracuse University, his alma mater. At the Wisconsin house, the granite countertops are green for the Green Bay Packers, his favorite childhood team.

The couple met working for American Cablesystems in Florida in the 1980s. They parted ways, but met up again in Seattle and married in 1993.

When they bought the house in Woodinville in 1996 for $640,000, it was run down but perfect for Max, their German shepherd. On a dog-friendly 2.17 acres, it is near walking trails and a 60-acre off-leash dog park. Ms. Dixon embarked on her first major renovation, spending about $1.2 million almost doubling the home's size to 8,000 square feet and installing a new master suite and an indoor, orange-and-blue half basketball court. There is also a man-cave area complete with bar, pool table and game area.

To get a break from the Seattle rain, the couple liked to vacation in Hawaii, and in 2004 they paid $3.7 million for a three-bedroom condo at Hualalai, a 865-acre resort with a Four Seasons hotel and fellow owners like former Starbucks CEO Howard Schultz. A year later, the couple bought the three bedroom right below their condo for $2.5 million.

One day in 2008, Ms. Dixon was in Rancho Palos Verdes, Calif., near where she grew up and where she often returns to see her family. Sitting at a carwash, she spied a magazine ad for a house for sale in the area. She soon bought an 8,000-square-foot waterfront spec house, with views of Catalina Island and the coast, for $5.875 million.

All the couple had to do to the house is paint the workout area orange and blue. Ms. Dixon furnished almost all of the six-bedroom home in one day after a trip to Ethan Allen, ahead of hosting her younger sister's best friend's bridal shower.

Although she felt the purchase, which was around 10% off the list price, was a good deal, Ms. Dixon doesn't view the property-or any of their homes-as investments, and doesn't track their values.

Max died in 2001, after which Ms. Dixon told her husband no more dogs. In 2010, Mr. Chapple surprised Ms. Dixon with Spence. The trouble was that dogs aren't allowed in the Hualalai condominiums. So Mr. Chapple bought a house across the street. Ms. Dixon refused to stay there because it was so run down, resulting in a stand off: Mr. Chapple and Spence stayed in the house, Ms. Dixon in the condo.

A year after Spence, Mr. Chapple surprised Ms. Dixon again, this time with a fishing cabin on Madeline Island, Wis., purchased for the full list price of $798,000. Born in Ashland, a ferry ride away, Mr. Chapple had spent many summers with his grandparents on the island, part of the 22-island group named the Apostle Islands on Lake Superior.

Ms. Dixon embarked on a $1.8 million renovation project of the three-bedroom. Among other things she installed radiant heating, added a master suite and redesigned the lower level. They also added a one-bedroom guesthouse and a two-car garage with office space and bathroom. She calls its present state "chic cabin".

Meanwhile, the couple sold the upstairs Hualalai condo and the run-down house across the street. They spent $3.6 million on a 1.6-acre lot in the Kukio Golf and Beach Club, next to Hualalai. They hired Tai Sunnland of Oahu-based Sunnland Architects to design a home with Hawaiian, Balinese, and Southeast Asian design elements. Finished in 2016, "Hale 'Ilio", or "Doghouse," is 9,000 square feet and has indoor and outdoor kitchens and living rooms, a media room (for watching sports), an orange-and-blue bathroom and a pool with a shallow-water terrace. The couple uses their remaining Hualalai condo as a guesthouse, and rents it for $1,200 to $2,500 a night.

Last summer, the couple bought a 3,000-square-foot house in a senior living community in Redmond, about a 5-minute drive from their Woodinville home, for $1.3 million. Ms. Dixon says her husband is threatening to stay in the Woodinville house alone, because he likes the space, but she says it is time to downsize. She's in the middle of what she expects will be a $150,000 renovation.

While she works on that, Ms. Dixon goes through her punch lists at her other locations. In Rancho Palos Verdes, there are niggling tasks, like getting the handyman to caulk the sinks and fix that cracked marble. The Hawaii condo just got bathroom renovations and new furniture.

Ms. Dixon says that although her estate management is exhausting, it is also oddly relaxing because it has become so routine. "I don't think about it, because I do it year after year," she says. "I can't remember a time when I didn't have a house project."

Write to Nancy Keates at [email protected]