The switch backs are easy. Just a lot of of them, like 12 if I remember right. There is a long up hill from the reservoir back up to the high country. The Red Canyon Overlook is worth a slight detour. Vernal is a great little town.
We have travelled that route several times and also the state route on the West side of Flaming Gorge. At any time, the road surface on one may be better than the other. The route into Vernal is the same whether you go East or West around Flaming Gorge. Our last trip on that route was about 5 years ago so can not advise on current road conditions.
The 10 mile or so decent into Vernal from the North has some grades in the 8% range. I seem to remember some 15MPH switchbacks. The first time I did it I overheated the trailer breaks just as we reached the bottom of the grade. On subsequent trips, I geared down early, even using 1st gear at times with good results.