The North Fork Yuba River continues to fish well from the top of the watershed, down to the lower reaches below Downieville. Water temps have dropped a few degrees with the colder overnight low air temperatures. Fishing pressure is extremely light, and you'll be able to find complete solitude now, especially mid week. Water levels are at their fall season low concentrating the trout into the bigger plunge pools, and runs. Look for pockets with some depth to them, I often find the bigger fish in these small areas.
Same dry / dropper rigs apply, a big bushy rubber legged stimulator or the equivalent, with a red copper John underneath. Purple is another great color. Don't forget about hoppers and ants in the afternoon when warmer air temperatures make them more active. For aquatics, the Psuedocloeon mayfly spinner fall has been on one day, and sparse the next. A few big Pale Evening spinners in the mid morning, and a resurgence of caddis during the day. It's not necessary to be on the water early with these cooler temps, starting at 10am is fine.
In the weeks to come focusing on lower down in the watershed will be of importance, remember you're chasing the happy zone of water temps that are 57 to 63 degrees. By October you'll want to be below Downieville. At the end of October bring your streamers as the brown trout will begin their fall spawning migration up from Bullards Bar reservoir. I like to bring two rods, one for dry / dropper rigs and indo set ups, and the other dedicated for streamer presentations. For the streamer rod I use a WF floater, and a sink tip for the deeper pools.