Families are life-giving accidents of nature. But they each come from somewhere out of the past. Knowing where you're from can help you discover who you are, and where you might be going.

When I got the chance to take a summer off, we struggled with how to use this gift of time. My first thought was to bike across the country, myself. But Cheryl said, "You can't take this time just for yourself; why can't we go with you?"

Well, that seemed like the right idea, but how would we get five people between the ages of 7 and 48 across the country on bikes. What was the route, where would we sleep, how would we carry our stuff, what if the kids couldn't do it ... the questions were endless.

So I started reading accounts of others who'd gone a long way on bikes, some alone, some in groups. After the fourth or fifth book, I woke up one morning and realised what the core idea of our trip would be: bike from one end of the continent to the other, through the hometowns of each of our kids' grandparents. Miles City, Montana, Council Bluffs, Iowa, Indianapolis and North Vernon, Indiana. It made kind of a straight line.

And it got me thinking about my own past. I was born in Boston, and ended up in Gig Harbor, WA. My mother had joined the "Mayflower Society" because her father's forebears in the 1600's had married into the Eaton family from that ship, in Eastern Massachusetts. So, dipping the rear wheel of our bikes into the Atlantic at Plymouth Rock, and the front tires into our local extension of the Pacific, Puget Sound made a neat set of bookends for both my life, and the trip itself.

The other four in our family hadn't ever seen the East; Cheryl had spent a year getting her RN in St. Louis in 1973 and spent her early childhood in Indiana; other than that, no one had been east of Colorado. So the West, our familiar turf would pull us toward the end, and the unfamiliar East (and the blank space in the middle) would intrigue us at the start.

I hatched this plot in the shower one morning; that night, I announced it and started pulling out maps, figuring where to go, how to connect the six dots we already had. We were on our way.