Oregon Trail is a narrower groomed trail / road that is usually open only in the spring.
To find Oregon Trail, proceed down Freeway on Solitude.
As Freeway cuts through a gap about 2/3rds of the way down.
Look to your right (north) for a traverse that ends at a horizon line.
Follow the groomed Oregon Trail all the way down to the base of Silverado.
This trail twists and turns and is narrow in places, so you should be a strong intermediate to have fun on this.
You will get to see some beautiful parts of Squaw Valley that most skiers don't get to see on this trail.