Pacoima Canyon has a crazy history - it was treated quite poorly when autos were introduced into the forest system, but much of the abuse was halted by incorporation into the Angeles National Forest.
We'll start at Dillon Divide and go east. We'll check out the mining tunnel, the southern end of Dagger Flats trail, more route finding in Dorothy and maybe even Gordon Canyon.
The road back up to Mendenhall Ridge Road is clear in satellite view, so the mileage reflects trying that - likely the mileage will be more like 12 miles.
Stats: 2500' gain, 15 miles.