Just like a good idea in a comic strip, it all started with a light bulb.

"It might be the most expensive light-bulb ever," said Anita S. Henehan, whose small purchase 10 years ago prompted her to sell her home in Ladue and begin a four-year odyssey in a 42-foot recreational vehicle.

Now, she has written her second book — "Tales From The Road" — about going mobile.

"My friends thought I was crazy when I did it. I'd never been into that sort of camping thing ever in my whole life," said Henehan, a mother and grandmother.

"I was kind of spoiled," she said with a laugh. "I loved my comforts."

While she firmly believes she has found true happiness through RV-ing, that discovery began with tragedies. In 1979, her first husband was killed and she was injured in a boating accident. In 1989, one of her three sons committed suicide.

"First, I was busy raising three sons and running two pharmacies by myself, and then there was my son's death. I spent my time doing what needed to be done," she said.

In 1990, she remarried. She and her husband, Paul Henehan, began bicycling. In 1995, they bought a small pull-along trailer so they could go to out-of-town rides without worrying about lodging.

"So when we got back from a trip, we stopped into an RV dealership to get a little bulb for the trailer bathroom. The next thing we knew, we were selling the house with a pool and an acre of ground and pretty much everything we owned to buy a 42-foot Holiday Rambler Navigator."

For the next four years, the couple had no fixed address as they spent their time crisscrossing the United States. Realizing they needed a place to receive mail, they bought a townhouse in St. Louis and settled down, a bit.

"We're gone at least four months out of the year now," she said. "We always spend three months in Florida in the winter and a month in Colorado, where we have family."

Henehan's husband does the driving, but she vows to someday learn how to pilot the vessel.

"I did drive one time, when Paul had to use the bathroom, when we were on a straight, flat stretch of road," she said. "It was the quickest bathroom break he ever took."

Several years ago, Henehan wrote "How To Run Away From Home After 50," which chronicled her lifestyle change. This latest book, subtitled "Adventures of Mid-Life Runaways" is more of a practical guide, chock full of dos and don'ts for those who own an RV or have toyed with the idea of buying one.

"The absolute No. 1 rule is: 'Start small.' Rent, don't buy, a tiny trailer and see if you and your spouse and family actually like it. Go for a day or two, not a full week."

For Henehan, RV-ing is far more than a method of vacationing.

"To me, it's freedom. You can go wherever you want and, if you don't like it, you can go somewhere else," she said, adding that the even-better aspect of the pursuit is the people she meets.

"There is a special camaraderie among RVers. No matter where you're camping, if you have a problem, there is always someone there willing to help you. And then you help others when they need it.

"In my opinion," Henehan said, "that's the way the whole world should be."