>>920723Trim work is trimming marijuana nugs. In that area it can colloquially refer to any 'paid-in-cash' work on a pot farm.
If you're unaware, a lot of world-class weed is grown illicitly in Northern California. Three of the northern counties grow most of it: Humboldt county (Redwood National is here), Mendocino county, and Trinity County. Together they are known as the 'Emerald Triangle'. If you're driving up Highway 101 in the autumn, it will be inescapable-- tens of thousands of bums, deadheads, and transients find their way to NorCal, trying to make some easy money.
Pic related: the prototypical 'trimmigrant'.