From Brigham City, UT, to Salt Lake City, a highway, maybe US-89, east and parallel to I-15, has fairly heavy traffic. UT-68 and US-89 from Salt Lake City to Provo is mostly through built up areas. To go to the Grand Canyon from Salt Lake City, I highly recommend US-89 and Alt US-89. They are 2-lane roads with light traffic running through scenic countryside with occasional small towns. (Springfield to Fairview was the only exception, with nearly 50-miles with little civilization along the road.) Much of the route follows broad valleys, with little climbing. Campgrounds and motels are available. Bryce Canyon and Zion national parks, both spectacular, are within 20 miles of US-89. Alt US-89 goes from Kanab, UT, to the North Rim of the Grand Canyon. Getting from the North Rim to the South Rim is almost 200 miles of mostly empty desert with a long coast down from Jacob Lake and some stiff climbs out of the Colorado River valley and up to the South Rim from Cameron, AZ.