Take a look at this route in Google Earth. It doesn't look too bad, but don't take that as a recommendation because I don't know. You can view some or all of this in "street view" - actual photos of the highway.
My recommendation would be to call the local NF Ranger station and ask them. Here's what Google Earth has to say about the route and the ranger district:
- "This byway crosses the Uinta National Forest between the cities of Nephi and Payson. It climbs to over 9,000 feet in elevation and provides breathtaking views of Utah valley, the Wasatch Mountains and 11,928-foot Mount Nebo, the tallest mountain in the Wasatch Range.
The Nebo Loop Byway is a photographer's dream with many overlooks and wildlife viewing opportunities. The brilliant fall foliage of the Uinta National Forest is hard to match anywhere in the nation.
Along the byway, numerous campgrounds, trail systems and popular horseback riding areas are available for exploration. A unique scenic feature is the Devil's Kitchen Geologic Interest Site with picnic facilities, a paved trail and observation deck. The spectacular red color of this amphitheater, with its many spires reminiscent of Bryce, is a brilliant contrast to the mountain greenery surrounding it. The eroded sandstone formations startling red color adds contrast to the mountain greenery found through the rest of the byway.
The Payson Lakes Recreation Area, 12 miles south of Payson, offers hiking on paved trails, improved picnic areas, camping and excellent fishing. This byway also provides backcountry trail access into the Mount Nebo Wilderness Area.
The 38-mile byway takes about 1.5 hours to complete. It is closed in the winter.
For more information contact Spanish Fork Ranger District 801-798-3571
Hope that helps.