TOOELE — If there's one thing that Gregory M. Franzwa feels in his heart and soul, it is "the power of place."

"That's a phrase my old friend Stanley Kimball told me. He used to talk about 'the power of place, the spirit of locale.' That's been guiding me ever since. It's what you feel when you stand in the ruts left by thousands of covered wagons," he says. "You get out there, and if you don't feel it you're either dead or don't know history. If you do know history, there's tremendous meaning in being able to stand in those ruts."

Franzwa has spent more than 40 years tracking "the power of place" across the American West. He is the author of some 20 books. He was a founding member of the Oregon-California Trails Association in 1972 and of the Lincoln Highway Association some 10 years ago, and he is in the process of writing a series of state-by-state books on the highway.

His most recent book, "The Mormon Trail Revisited" (Patrice Press, $24.95, patricepress.com) tracks the 1846-47 route of the Mormon pioneers, providing driving directions to guide motorists along the 1,300 miles of trail, wherever it can be reached by a family car.

"We tell you where to turn the steering wheel," he says.

Although he is not a member of the LDS faith, Franzwa has long been fascinated by the Mormon migration and the tremendous undertaking that it was. "This exodus was the most amazing thing. There's been nothing like it before or since. You think of the 2,500 humans and 500 wagons that left Nauvoo and camped at Sugar Creek. That has to be the biggest wagon train in history times 10."

Franzwa and his wife, Kathy, who now live in Tooele, spent three years tracking the trail. They follow the mass exodus across Iowa, where the "adhesive mud so frustrated the pioneers' plans to cross the Rockies that year that they had to hole up along the Missouri River. That must have been so discouraging for them."

He then follows the trail that Brigham Young and the lead wagon train followed across the plains and into the Salt Lake Valley. "We found every single campsite," he says.

His purpose in writing the guide was twofold. He wants to help people get there — "right in the traces. Right where the mules and oxen and wagon wheels left those scars. To get out of the car and stand in those ruts. Or, on the roads, even if the ruts have been covered with gravel, oil or concrete. Stop the car in an isolated place, with nothing man-made in sight. Turn off the engine. Leave the car and listen to the sound of silence. The feeling will still be there, for all those who know what happened along the way."

Don't be surprised, he says, if you get the "willies big-time. I've had perfectly normal people tell me that they have stood in the sandstone scar over Deep Rut Trail in Wyoming or in the trench over California Hill in Nebraska and simply trembled with emotion."