It's the ultimate side gig. See the country and make some cash

Mark Dougherty makes a few thousand extra bucks a year as a hired driver for people who need to get their cars and moving trucks across the country.

The retired 70-year-old charges $10 per hour driving time and uses Google (GOOGL) maps to estimate his fee, plus expenses like one-way plane tickets, gas, lodging and meals.

He charges an additional $60 to cover having his wife transport him to and from the airport. Dougherty advertises mostly on Craigslist and MyFamilyTravels.com, and he is occasionally tipped (such as on a recent 17-hour drive from Houston to Phoenix, when he received an extra $270).

If you search for "hire someone to drive your car cross country," you'll get lots of companies and individuals vying to help you: WaynesDrivingServices.com, DriverLES.com, ProfessionalDrivers.com, IDriveYourCar.com, to name a few.

These "driveaways," or hired cross-country drivers, are the ultimate side gig for many – retirees in particular — who want to get out of the house, make a few dollars and travel, said Frank Futie, who contracts about 30 drivers for his companies, Rented Truck Driver and Uride Idrive, which move cars, RVs and trucks.

Car owners love when a person is driving, rather than shipping, their vehicles, too: It can be cheaper with less chance of damage.

And while it's possible for aspiring drivers to work with established companies, there are also plenty of opportunities for those just wanting to take a cross-country adventure to pair with a car owner through travel forums and social media. The driver usually gets reimbursement for some or all trip expenses and the car owner gets their car somewhere cheaply.

Sound like a good deal? Consider the following before hitting the gas.

Cover your liability and double-check safety

Forums on travel websites like HoleIntheDonut.com and MyFamilyTravels.com feature hundreds of posts by car owners who need to get across the country for one reason or another but don't have the time or would prefer not to be behind the wheel.

Other car-less travelers would prefer to drive because their dog doesn't like flying, they want to take a national park vacation, or they are moving and want to take their time to see the country while doing it.

After Washington, D.C.-based attorney Jill Williamson posted an ad on a forum with a request for someone to get her 2012 Nissan (7201.T-JP) Juke to Seattle for an upcoming move, she got "tons" of takers, just for gas money. Williamson picked the first responder who sounded interesting — a New York musician making a move to Los Angeles.

To prepare, Williamson asked for a copy of the driver's license and driving record. Williamson checked that her insurance would cover the third-party operator and got the vehicle a full checkup.

Because a driver may not be familiar with the car, he or she should plan to have their own roadside assistance such as AAA in case an emergency tow or flat tire occurs, Dougherty said. A truck he once drove from California to Florida broke down three times and required a tow for the last five hours of the leg.

It was going to cost Rachel Ishofsky upwards of $1,000 to ship her car from New York to Los Angeles, versus the $350 gas reimbursement she negotiated with a driver she found on Facebook.

"I thought, why not use this as an opportunity for someone else to have an adventure?" she said. "People were so jazzed."

Ishofsky and the driver worked out how to insure the car and driver and what would happen if the car broke down (Ishofsky would pay for repairs). Ishofsky also bought new tires for the journey. The two agreed on 14 days to transport the car and to check in periodically.

"It's an exercise in trust," Ishofsky said. "I'm helping him and he's helping me."

For regular cash, working with a company is key

Though it's more expensive for car owners to hire a company to match a driver to their car, it is likely to get there faster and with less risk. Drivers are paid in addition to receiving reimbursement for expenses, and because they are heavily vetted, they cannot sign up for a one-off driving trip — they need to be committed to regular assignments.

Futie prefers to hire retirees for their reliability and scheduling flexibility for his moving truck driving business. They earn an average of $300 per day plus expenses and can easily make up to $3,000 per month part time (it works out to about $25 per hour), Futie said. Hauls often involve transporting snowbirds' cars to and from the Northeast to Florida during season changes.

About 10 percent of all inquiries to Mark Duda's websites, CrossCountryDriver.com and DriveCartoFlorida.com, are about how to become his drivers, which he pays $500 to $1,200 per trip plus expenses (Duda says he is not hiring anytime soon because he already has a waiting list).

Driving is appealing to lots of types of people, Duda said. "Many say they would do it for free."

Driving for a company means you're usually better protected against the unexpected. Duda only takes vehicles less than 7 years old and 150,000 miles to limit chances of breakdowns, for which the owners are charged for time and expense.

Know your limits

Dougherty learned the hard way that independently arranged jobs can go wrong. A client once backed out after he'd already purchased his flight (he now requires clients book his one-way airfare first). Another client didn't pay as agreed.

Both Futie and Duda said their drivers can choose to stay in a destination for any amount of time they want and choose how much they want to work, where they want to go and how far.

"If you're one of my drivers you get steady work when you want it. It would be scheduled well and you get a comfortable car," Duda said.

Look for commercial discounts to drive

If you're mostly interested in reducing expenses on a drive, rather than earning income, you can also seek opportunities with car and RV rental companies that need to get vehicles to other destinations.

Austin, Texas-based marketing consultant and DealsAtx.com blogger Judah Ross came across an opportunity on CruiseAmerica.com to move an RV from Phoenix to Salt Lake City over the holidays. Though he wasn't paid to do it, the RV use cost him only $20 per day including insurance.

At the full price, five nights with the RV would have cost him $525, $200 in mileage charges, plus $300 in gas. Instead, he spent about $400 total.

"You really have to keep on top of it and the deals go quickly," Ross said. "It's got to work out with your schedule."

Remember driving is taxing on your health

You'll have the best shot of becoming a driver-for-hire if you're a nonsmoker, have clean driving, credit and criminal records, pass a drug test and are trustworthy, Duda said, particularly because car owners often pack their cars with personal belongings.

Dougherty has even driven a client's Bernese mountain dog on a haul. Patience and comfort with being alone is also key, since you might hit unexpected weather or traffic delays that could add hours to your trip. Your health must also be good, Futie said.

"There's certain looks you see in certain parts of the country at certain times of the year and that's worth doing for free sometimes," Futie said.