NEW YORK (MainStreet) -- For Americans looking to add some much-needed income to their retirement savings once they leave the workforce, boundaries - geographical and otherwise - aren't all that necessary.

Take Carol Merchasin, an author and former law firm partner with Morgan, Lewis and Bochius in Philadelphia, who's now living with her husband in San Miguel de Allende, Mexico.

"My husband and I boosted our retirement income by leveraging what we did before we retired into less stressful and more part time employment that doesn't require being in an office or even in a particular place," Merchasin says. "When I left my law firm, I continued doing training but only as an independent contractor, often doing webcasts from Mexico. Now, ten years later, at almost 70 years old, I still do webcasts and I develop and audit training programs. All from wherever I want to be."

Merchasin also published a book of essays on Mexico called This is Mexico: Tales of Culture and Other Complications and does speaking engagements on Mexican culture from a U.S. expatriate perspective. Her husband, also a lawyer, invested in a small property with three apartments that he now rents out to short term visitors to San Miguel. "Our long term strategy has been to support ourselves without touching our nest egg until we were 70, but we are still keeping with that strategy for a few more years," she says. "Boosting retirement income for us has meant not taking anything out and allowing it to grow as long as we're still able to work comfortably at our own pace."

Financial experts say that Merchasin is on to something, and that, since Americans may not be saving enough for retirement, they should seek extra income while they're in retirement. "Living comfortably in retirement isn't so much about how much money you have, but more importantly what counts is having a solid cash flow plan in place that includes a very clear income and distribution strategy, says Gary Plessl, a certified financial planner who co-authored The Book on Retirement (Richter Publishing, 2015). 

The data support their notion that many Americans just won't have enough cash saved up for their after-work years, and will need other avenues toward income once they retire from their full-time careers. "Millions of Americans are in danger of not having enough money to maintain their standard of living in retirement," states the Center for American Progress in a new report The Reality of the Retirement Crisis. "The problem is getting worse over time."

As of 2013, the median retirement account balance among all households ages 55 to 64 was only $14,500, the CAP reports, and almost one-third of Americans in the workforce haven't saved anything for retirement.

If you're in the same leaky boat, and are wondering how you can earn extra income in retirement, Plessl and Houser offer a few key tips to follow.

"Stretch your mortgage," they say. "If you find yourself with a mortgage in retirement, stretch it out as long as you can. Just because it's debt, in this case it doesn't make sense to pay it off quickly. Retirement is all about cash flow, and paying more than you must on a mortgage is counterproductive to cash flow."

Also, take Social Security as early as possible. "If you're over 62 years of age, take social security as soon as you can get it," Plessl says. "You've been paying into the program long enough, and it's better to spend the government's money than your own money. The only exception to this when it would make sense to wait until age 65 is to provide more room for Roth conversions prior to full retirement age. It's best to speak with your financial advisor and accountant regarding the best strategy for your situation."

There are plenty of great ideas to hike income in your retirement years -- some more common than you think. You can use your home mortgage to generate more money, says Christopher McGill, chief executive officer at Philadelphia-based East River Bank.

"With such low interest rates one can use the equity in your home to get a long term loan to consolidate other expenses -- auto, credit cards, student or repairs -- into a single, low payment -- freeing up substantial cash flow and potentially creating a tax deductible interest," he says. "Another option is to investigate a reverse mortgage - just make sure it works for you."

One other way to use your home to generate more dollars in your 60s, 70s and 80s is turn it into a rental options for travelers. "I believe the new American dream is having a home that allows for extra rental income, through home sharing ala Airbnb," notes Susie Wyshak, an Airbnb host in Oakland. "While not every area allows it, the option to have a renter to supplement income and have someone around, if you live alone, is pretty unbeatable."

The key takeaway is this -- if you haven't saved enough for retirement, start thinking about bolstering your retirement fund with extra income. You'll appreciate the additional cash, and you'll be plugged in to a brand new experience in your golden years.