This trail is moderately technical with a number of rocky sections but also completely runnable.
The Sunset Trail is popular particularly in the summertime as it's higher up Mt. Lemmon and connects runners to the Marshall Gulch area without having to drive all the way up through Summerhaven. It's a common parking/starting point for visitors as outings can also easily head the other direction to the top of Bigelow via Bear Wallow under the road, or visitors can also head to the Butterfly Trail
. Additional parking also exists across Catalina Highway near the Butterfly Trail
From the Sunset parking area, head west down the hill on the dirt road. Before long, you'll reach an intersection with another road. Head straight across it to the singletrack pretty much directly ahead which then winds left up a gentle slope. The rest of the trail is pretty much straightforward all the way until crossing the creek right before the Marshall Gulch Picnic Area. There you'll find a bathroom and both the Lower Aspen Trail #93
and the Marshall Gulch Trail #3
There's reasonable tree cover for a good portion of the way while other sections are more exposed. Coming back from Marshall Gulch is definitely much more uphill, but it's pretty scenic the entire way.