Sustainable? Organic? How about delicious? Nathalie Jordi steers a Lexus GS 450h on the byways of an agricultural revolution

Wisconsin officially designated milk as its state beverage in 1987. Legislators have also passed directives to honor corn and the badger as the state grain and animal, respectively. Over in Minnesota, too, milk and badgers are among the state's emblems, although old-timers wryly recount a failed 1973 citizen proposal to name the wood tick the state animal (since the loon was already the state bird, Minnesota would have become the loon-and-tick state).

The Upper Midwest's reputation as America's drowsy, staid breadbasket exists for a reason, although rumors of a quiet revolution amid the cornfields and GMO soybeans have begun to burble. Hearing whispers of a small militia of third-wave Laura Ingalls Wilders growing papayas in retrofitted barns, building straw-bale outhouses, and using wind turbines to power their homes, my partner in crime and I judged a recon mission appropriate. Perhaps a Lexus GS 450h hybrid would help us blend right in.

Day 1: Browntown to Bayfield, Wisconsin (395 mi.)

The best way to digest sustainability, as innkeeper John Ivanko makes clear on our trip's first morning, is to toss it in dill, douse it in yogurt and berries, or slather it in creamy butter and eat it, still warm. Eleven years ago, John and his partner, Lisa Kivirist, embarked on second careers as "eco-preneurs," setting up their 100 percent off-grid B&B—the Inn Serendipity, in Browntown—as far from the corporate world as state borders would allow. Now, they grow so much of their food that their largest annual edible expense is coffee. On glimpsing our muscular, high-performing vehicle parked in front of the farm's wind turbine, John cocks an eyebrow. It need not be said that the only ecologically friendly way to cover 900 miles in three days would be to sprout zero-emission wings from our shoulders, but, hey, at least it's a hybrid…right? John's eyebrow stays cocked; his electric car plugs into a solar panel.

Heading north on Highway 69 in our sleek sedan, slipping over hillocks and through gnarled wood dells, we whip past squat red barns and black-and-white cows. The corn has been planted nearly to the road, but where it hasn't, spiky violet asters, canary yarrow, and Queen Anne's lace reach up toward the seemingly infinite sky. Stopping in Madison—a town whose Saturday farmers' market, food co-op, and upscale restaurants (l'Etoile, Harvest, the Old Fashioned) put, from a sustainability perspective, most major American cities to shame—it becomes obvious that the Middle is much more progressive than people on the coasts might think.

Once past Madison, we join Highway 51, the less harried adjunct to I-94. Construction works have obfuscated road signage, so we rocket eight miles past our next stop, the Midwest Renewable Energy Association in Custer, before pulling over for directions. In a Western-boot shop next to a bar advertising happy hour from 3 to 6 P.M., a pretty girl in high-waisted jeans and a cowboy hat greets us, snapping her gum. "Oh, the MREA!" she exclaims. "My mom teaches there." We must look surprised. "She's a carpenter who specializes in straw-baling and cold-bin composting," the girl explains.