This is part of that grey area between MTB and gravel. If you're feeling bold, give this section a go. It's listed as a "blue" on trail forks and I think that's accurate. Some parts are steep and challenging on a rigid frame. On 37mm tires it was tough, and there were parts that I walked, but with 45mm+ tires and low pressure you might have more luck. Though its challenging, it creates a nice loop if you descend out City Creek towards the Capitol, and get back on the Sandhurst fire road to the west of Ensign