You've run the numbers, and have done your early retirement planning, but something just isn't adding up. Costs seem to be out of control. Though you've read that your combination of 401(k) and IRA savings makes you eligible for early retirement, you just can't figure out how other people do it.

Most of the time, there's one key factor at play: sky-high cost-of-living expenses. I know the feeling: when my wife and I lived in Washington, DC, our cramped 600 square-foot apartment ran $1,550. Now we live in a rural Wisconsin community where our 1,100 square-foot quarters cost just $700 per month.

A move like that makes a big difference. But if you're ready for early retirement, the question becomes: where do I even start? Of course the cost of living matters, but so does the opportunity to connect with others, have access to the outdoors, and participate in a vibrant community.

While every situation is different—especially when it comes to the location of your close family and friends—some of the hard work has already been done for us by the writers at Kiplinger's.

The organization published a list in 2013 of the top cities for early retirees. Here are the top five, with a quick explanation as to how they earned their stripes.

No. 5: Sioux Falls, SD

Source: Seabear70, Wikimedia Commons 

I went to college in rural Iowa, so I'm familiar with the automatic shudder that accompanies the suggestion of living in an under-populated Great Plains state. But as the picture of the city's Falls Park shows, this part of the country is more than just desolate wasteland.

As you might expect, cost of living expenses are low: 15% lower than Chicago, and a whopping 55% lower than New York City , according to CNN's Cost of Living Calculator. The city has a population of 154,000, 24% of whom are between the ages of 45 and 64. And according to Kiplinger's, your Social Security and other retirement benefits are untaxed as well.

Of course, there are trade-offs. The closest major metropolitan area is Omaha, which is a three-hour drive. And be prepared for cold and snowy winters. Average highs from December through February are below freezing, and about 44 inches of snow falls per year.

No. 4: Sandy Springs, GA

Source: Glen Edelson, Wikimedia Commons 

For those in search of a warmer climate for early retirement, Sandy Springs is worth investigating. The city, located just north of Atlanta, has a balmy average high of 50 degrees in January. That means you can enjoy the 20 miles of Chattahoochee River (pictured above) frontage year-round. And let's not forget the year-round entertainment provided by Atlanta's college and professional sports teams. Residents can expect tax breaks--up to a certain level--as well.

On the flip side of living near a big city is dealing with traffic. Though you likely won't have to worry too much about a morning commute, a 2010 study by the Texas Transportation Institute said Atlanta had the 8th worst traffic in the country, with the average driver spending 44 hours in traffic each year. And summers can be hot, with average highs in the upper 80s and heat indexes that will probably force you to run the AC continuously.

No. 3: Alexandria, VA

Source: Zach Rudisin, Wikimedia Commons 

I'll admit right off the bat: we're a little biased about this one. Alexandria is home to The Motley Fool headquarters, so we think it should really be number one on this list.

There's a lot to like about the city. Located right on the Potomac River, historic Old Town Alexandria is full of cute shops and places to whet your whistle. If exercise is important to you, a biking/running path runs along the river and right past Reagan National Airport. And when you're in the mood for larger events, a short ride on Washington, DC's metro line lands you smack dab in the middle of our nation's capital. 

As with Sandy Springs, however, both traffic and an inordinately muggy summer will be on your menu in Alexandria. The city also has a relatively higher cost of living as well: over 40% higher than the previous two cities on the list. Federal and military pensions are also taxed, according to Kiplinger's.

No. 2: Cary, NC

Dancing in the streets in Cary, NC. Source: Town of Cary .

Never heard of Cary? It's the city of 150,000 located smack dab in the middle of North Carolina's Research Triangle.

Obviously, quick access to cultural and sporting events at the University of North Carolina, North Carolina State, and Duke University are a big draw. In Cary you'll find warm weather and lots of compatriots: over a quarter of residents are between the ages of 45 and 64. And it's hard to beat the cost of living: about 20% lower than Chicago, and over 50% cheaper than Manhattan.

While Social Security is not taxed in the state and some forms of North Carolina state and local pensions are given favorable breaks, retirees will have to contribute somewhat to public coffers. Any pensions that originate outside of North Carolina, and personal IRAs will can be taxed--though deductions are included as well. 

No. 1: Naperville, IL

Aerial view of Naperville. Source: City of Naperville .

Number one on Kiplinger's list goes to this city of 140,000 residents living 30 miles southwest of Chicago. Naperville has won many accolades, including Money magazine's 2nd-best place to live in 2006, and the wealthiest city in the Midwest with a population over 75,000. Naperville is close enough to Chicago that a quick Metra ride lands you right in the middle of the nation's third-largest city and one of the biggest cultural melting pots between the coasts.

The biggest drawback to retiring in Naperville is cost-of-living. Housing is 41% higher than the national average, and overall expenses are about 13% more than you'd have in an average community.