For a certain type of outdoorsy person, the Volkswagen VOW3.XE +2.39% bus was the quintessential vehicle of the 1970s and early '80s. Then VW buses grew hard to find and the Toyota 7203.TO +1.93% Pickup took its place, because it was cheap, had a reliable 2.4-liter, 4-cylinder engine that got good mileage, and you could sleep in the back. In the 1980s and '90s, the Toyota truck was it.

I bought my 1989 Toyota in 1994 from a friend of my brother's for $7,500, when I was 23. I was becoming a dropout and I didn't want to pay rent. I was after the freedom of an affordable car that I could live in, so I put a shell on the back, with a bed built into it. I was working seasonally as a river guide in Utah, then I'd take off and roam around. Being single (except for my dog), it was a pretty perfect living arrangement.

Now I'm 42, married and I own a house in Missoula, Mont. I have health insurance and even a lawn mower. I've moved on to more practical cars with more seats. But I can't get rid of the Toyota because of the sentimental value—road trips with different friends, or the time I rolled the truck on a dirt road. It had 42,000 miles on it when I bought it. Now it has 237,000. Every dent tells a story. It's become a symbol of my younger, simpler life.

Mark Sundeen , the author of "Car Camping" and "The Man Who Quit Money," on making his home in a pickup truck, as told to A.J. Baime: